Hope-Jones and the Dry Cell
by Colin Pykett
Posted: September 2003
Last revised: 22 March 2015
Copyright © C E Pykett
"It is a far, far better thing to have a firm anchor in nonsense than to put out on the troubled sea of thought "
J K Galbraith
While Robert Hope-Jones's organs could not possibly have run on a dry cell as he claimed, no doubt some of them were heard over the first radios 30 years later using the same power source for the high tension battery. Would he have approved?
Abstract. There is a widely held belief that Robert Hope-Jones's organs were designed to use so little current that they would run on a few dry cells, or even a single one, for months at a time. Even eminent organ historians have continued to repeat the story to the present day without apparently questioning it. Yet a little elementary analysis causes one to stop and think about the issues involved, and more detailed engineering investigations show the belief to be completely untrue. It is untrue because it would have been impossible, and this article proves it by examining some of the circuits and components Hope-Jones would probably have used. Not only his key actions, but his stop and combination actions are considered, and their energy requirements are shown to far exceed the capabilities of dry cells.
A consequential and intriguing question, therefore, is why Hope-Jones himself apparently encouraged the propagation of the dry cell myth. This also is addressed in the article which, besides the engineering issues, looks at some commercial realities of the late Victorian era and the approaches used by some other contemporary organ builders to power their electric actions.
The article demonstrates the phenomenal success of a misinformation campaign which has led scholars and other Hope-Jones pundits up the garden path for over a century.
(click on the headings below to skip to the relevant sections)
In the early days of electric actions
Robert Hope-Jones was a well known though controversial figure.
It is unfortunate that so much of what he did has become shrouded in a miasma
which is almost impossible to penetrate today.
There are many reasons for this, the obvious one being that almost his total
legacy in terms of surviving organs is lost.
Then there is that deplorable mass of published material which is characterised
less by erudition than by misunderstandings, errors, misinformation, rumours,
mischief and unrestrained enthusiasm.
Others who have forsaken scholarship at the mention of his name have merely
descended into emotive and subjective censure.
As if this is not enough, Hope-Jones himself contributed to the problems on
occasions, some unmistakable examples of misinformation occurring in his
surviving patent specifications besides an accumulation of anecdotal material
which is less easy to verify.
In this article I have therefore adopted a different approach to the investigation of a specific topic. Instead of appending an impressive-looking list of notes and references, which would be easy, there is not a single one. My excuse for this is the undignified quality of much of the literature as noted above. As an alternative I have taken an example of organ building technology which is popularly linked to Hope-Jones, namely the use of dry cells in powering electro-pneumatic actions, and examined it from an engineering viewpoint. Some interesting conclusions emerged. This approach has the advantage of highlighting things which will work and those which will not, regardless of cherished notions or received wisdom or what the literature says. It is as black-and-white a method as can be achieved against the difficult background in this case, and the outcomes illustrate why mythology flourishes when objectivity is sidelined.
This article first appeared in 2003 and it
has created considerable interest, judging by the volume of correspondence
received. Consequently Appendix 2 was added in July 2004 summarising the
dialogue which has taken place, and assessing whether the conclusions reached
needed to be modified as a result.
More recently (June 2009) a detailed technical analysis of Hope-Jones's actions has been posted on this site which expands the issues discussed here (see Robert Hope-Jones: the evolution of his organ actions in Britain from 1889 to 1903).
These illustrations of a dry cell (left) and a Leclanché cell are the earliest I could easily find. The dry cell sketch appeared in a publication dated 1913, and its dimensions can be judged from the size of the brass binding posts which would have been about 1 cm in diameter. Therefore it was a very large cell compared to those we are familiar with today, comparable in volume and weight to those which Robert Hope-Jones used to wave around at his lectures and demonstrations. The drawing of the Leclanché cell was in an old school book from the 1950's, though they had probably fallen out of use long before that.
Dry cells had only recently appeared at the time Hope-Jones was beginning his career as an organ builder. They were probably received enthusiastically by the general public, if only because they were able to replace the heavy and extremely messy Leclanché cells which hitherto had been just about the only portable source of power for things like electric bells. These had been invented by Georges Leclanché in 1866 and contained an open reservoir of corrosive sal ammoniac solution which had the annoying property of creeping out of the glass vessel in which it was contained. What happened if it was knocked over accidentally can only be imagined. The dry cell solved this problem by using a paste form of the electrolyte, which was also completely enclosed. Otherwise the two cells were similar in terms of their electro-chemistry. The dry cell was invented by Carl Gassner and became available commercially in 1888, only a year before Hope-Jones resigned as a telephone engineer to become a full time organ builder. Because of the emphasis he attached to the dry cell, as this narrative will show, one can probably assume that they were already well known to the public. In turn this probably implies that they had become almost an overnight success and that they were already widely available from hardware shops and the like.
Robert Hope-Jones playing his celebrated organ at St John's, Birkenhead, from outside the church c. 1890. The organ was demonstrated to thousands of visitors, having been transformed by Hope-Jones and the Liverpool organ builder Franklin Lloyd over several years, assisted by various members of the choir and some colleagues from the telephone company. Much of the work was done in the evenings in nearby rented premises. Note the cable snaking its way into the gloom within. No pneumatic assistance could have been used to operate any of the mechanism in this console, in particular the combination action, which must therefore have been entirely electric. This fact plays a key role in the arguments developed in this article. The reason why he chose to wear a mortar board, and which institution had granted it to him, are questions for which I do not have the answers. Some of the wording on the notice board is readable, confirming that this version of the photograph has been printed the correct way round - some others are a mirror image.
Hope-Jones seemed not to be averse to
statements or implications that his organs would work for months on a battery of
dry cells, or sometimes just a single one.
Such a cell gives a voltage around 1.5 volts.
On at least one occasion visitors to the Hope-Jones organ at St John’s church,
Birkenhead (the one where he was famously photographed playing a detached
console outside the porch as pictured above) were apparently shown “a single dry cell, about the
size of a two pound marmalade jar, capable of working a four manual organ for
For the benefit of those who do not buy marmalade, the description was of a
squat cylindrical vessel about 12 cm high by 10 cm in diameter, and there was
certainly a dry cell of roughly this volume still available commercially in the
1950’s and maybe later.
Today however, when the largest dry cell easily obtainable is the much smaller D
or R20 size, the Birkenhead description is of a very large cell indeed and
perhaps it explains why these anecdotes from so long ago seem to be taken at
face value – on the basis of the “such a big battery must have been OK”
type of argument.
Several other references exist in which Hope-Jones himself claimed that his
organs would work for long periods on a single dry cell. They are appended
to another article on this website, Hope-Jones at the College of Organists
This reviews a lecture he gave in which he repeated the claim a number of times.
Several other references exist in which Hope-Jones himself claimed that his organs would work for long periods on a single dry cell. They are appended to another article on this website, Hope-Jones at the College of Organists (read). This reviews a lecture he gave in which he repeated the claim a number of times.
But if we probe deeper several questions
For example, 1.5 volts is a very low voltage with which to push an electric
current through the windings of sundry electromagnets and relay coils, and it
would have led to a number of interesting (a euphemism) engineering problems in
Then the implication that any organ, let alone a large one, could run on such a
cell for a long period causes one’s eyebrows to lift after a little
And, depending on the type of circuits and components used in the organ, a bit
more arithmetic encourages positive disbelief.
If we add to this the fact that we know some of Hope-Jones’s organs did not
actually use dry cells at all, the story becomes mysterious indeed.
One is led to ask why he said (or allowed to be said) he used them when he did
The primary chest magnet used widely in
today’s electro-pneumatic actions has changed little from that introduced by
Hope-Jones around 1890.
It consisted of a hairpin-shaped yoke with a coil of wire on each arm, arranged to
attract a small disc valve thereby enabling a small pneumatic relay to collapse.
In turn this admitted wind to a larger power motor which did the heavy work of
opening the pallet.
The magnet is discussed in more detail in Appendix 1.
We shall not contribute to the controversy
as to whether Hope-Jones plagiarised this magnet and valve design or some
aspects of it from other inventors, as it is a matter of no relevance to this
article. The electrical resistance of the magnet is a parameter of interest here
though; in today’s devices it is typically 150 ohms whereas in Hope-Jones’s
case it was probably somewhat lower.
This is because it is cheap and easy today to obtain fine copper wire covered
with a very thin but tough insulating layer, whereas over a century ago a thicker
silk or cotton covering was more usual, or the windings relied on techniques
such as wax impregnation for insulation.
This would have meant that Hope-Jones’s magnet coils might have contained less
wire of a given gauge than modern ones for the same size of bobbin, hence they
would have had a lower resistance. Of course, the resistance of
Hope-Jones's magnets could also have been different from today's figures by
intention. For the purposes of the engineering analysis in this
article a value of 100 ohms was used; this seems a reasonable assumption because
the evidence suggests the actual
magnets had resistances lying either side of it (see the Appendices).
Of course, the resistance of Hope-Jones's magnets could also have been different from today's figures by intention. For the purposes of the engineering analysis in this article a value of 100 ohms was used; this seems a reasonable assumption because the evidence suggests the actual magnets had resistances lying either side of it (see the Appendices).
To a man, pundits of the day opined that
the higher the resistance the better, presumably from the obsessive desire to
prolong battery life.
Thus figures of several hundred ohms were extolled routinely.
As far as it goes this argument cannot be gainsaid, but it obscures some basic
facts about electromagnets.
The pulling or lifting ability of a magnet depends on the current
flowing through it and the number of turns of wire on the coil.
Unfortunately, increasing the number of turns increases the resistance and so
decreases the current.
To redress this the wire can be made thicker, but a practical limit is then
reached by the maximum bobbin size which can be accommodated in the space
There is not much space in the type of magnet we are discussing here, therefore
in cases like this the wire has to be thin and the current can only be raised to
a reasonable value by increasing the voltage.
Very low voltages are seldom practical with electromagnets.
These design rules for electromagnet coils
are expressed by some simple formulae which Hope-Jones must have been familiar
with (he was a Member of the Institution of Electrical Engineers and a former
telephone engineer, whose day job would have been dominated by electromagnet and
Inserting the dimensions of his magnet into the equations shows that a coil
resistance of around 100 ohms would indeed have been obtained using reasonable
In turn this means that the current consumed by his action magnet would have
been much greater than by those of some of his competitors, who appeared to
prefer larger magnets with resistances of several hundred ohms.
It is important to note that the larger magnets did not necessarily lead to
better actions, however.
Because of the similarity of today’s magnets to those used by Hope-Jones, we can easily do some tests to see whether a dry cell would drive them successfully. In fact a single dry cell shows no sign whatever of opening the valve of a 160 ohm chest magnet even in the absence of wind pressure on the disc opposing the magnet pull. Two cells in series, delivering 3 volts, will just pull in the valve but again only in the absence of wind. It is necessary to use 10 volts or more to get anything like a reliable response when wind at low to moderate pressure is present. With higher wind pressures it is necessary to use even higher voltages, bringing us up to the 15 volts or so with which these components are designed to operate today. Even allowing for the probable difference in resistance, this is a long way from the single dry cell popularly associated with Hope-Jones’s electric actions! With several dry cells in series the problem is lessened, and in his McEwan Hall organ in Edinburgh “a few dry cells” were apparently used. Therefore the marmalade jar statement has to be interpreted with a degree of license.
Problems of battery life are also
Consider the case of an organ with conventional slider soundboards –
Hope-Jones used these for some years before he moved towards the unit chest
concept developed with Wurlitzer in the USA.
Let us look at a case where a chord of four notes is played on one keyboard
coupled to another.
A total of eight chest magnets will be energised.
If they each have a resistance of 100 ohms and are driven at 12 volts (8 dry
cells in series) the current consumption will be nearly one ampère (A).
Adding another magnet for a pedal note, plus two more for the same note coupled
to each manual, the total current becomes about 1.3 A.
Such homophonic playing characterises hymn tunes which would have been rendered
in a near-seamless legato, meaning that this current would have been drawn
almost continuously during a hymn except for the short breaks between verses.
Let us note in passing that this represents quite a challenge for any dry
Moving on, the duration of a hymn such as Jerusalem the Golden to the tune Ewing would be about 2 ½ minutes if four verses were sung at 100 metronome beats per minute. Simple arithmetic shows the required storage capacity of each cell in a battery which would just power the action for the singing of this hymn would therefore be about 0.05 ampère-hours (Ah). Therefore, if we assume there were two Sunday services at each of which five similar hymns were sung, the required battery capacity per Sunday to service the ten hymns alone would be 0.5 Ah. This figure can reasonably be doubled to cater for psalms, canticles, anthems and voluntaries, bringing it up to about 1 Ah per Sunday. Therefore to power the action for a period of six months (26 weeks) as quoted in the marmalade jar claim, a 12 volt dry battery of at least 26 Ah capacity would be required. This is a substantial figure, about half the storage capacity of a typical car battery today. It is doubtful whether the rudimentary zinc-carbon dry batteries available to Hope-Jones would have come anywhere near this level of performance.
This minimal analysis excluded any use of the organ for recitals, teaching, choir practices, tuning and additional services. It also neglected the significant currents required for swell shutter control, coupler relays and those performing the multitude of other functions in the key action of a Hope-Jones organ. Note we have yet to add the power requirements of the stop and combination actions; these will be considered later because they inflate the problems massively. Moreover, we were certainly not using the full resources of a four manual organ in the analysis, as quoted in the marmalade jar statement. Crucially, such an organ if built by Hope-Jones would contain a large number of octave and sub-octave couplers (as would his smaller ones). Using just one of these would more or less double the current consumption at a stroke. Realistically we should therefore need to provide a storage capacity many times the figure arrived at above. Conservatively we might triple it, bringing it up to at least 80 Ah. Even the large marmalade jar type of dry cell could not cope with anything like this; the zinc-carbon type of dry battery then available was intended only for infrequent low current work such as powering electric bells, or telephones in subscribers’ premises. It was made large so that it would last for a long time, a time approaching its shelf life, in these undemanding applications.
Even if its storage capacity had been adequate for organ applications, there would have been problems of short term “fatigue” due to the production of hydrogen, and in the 1890’s it is doubtful that these problems were fully understood nor soluble. Even today the fatigue problem has not been solved, as anyone knows whose flashlight gets dim too quickly but temporarily recovers next time it is switched on. This might be OK for a flashlight but not for an organ - it would have been little consolation to a congregation to hear the organist calling out that they would be able to sing the last verse of the current hymn after a five minute break (and it was indeed frequently the case that a battery powered organ would not make it through to the last verse).
To achieve the required storage figure
means we have to consider secondary (re-chargeable) cells such as the lead-acid
accumulator, and a capacity of 80 Ah is typical of a heavy-duty 12 volt vehicle or "leisure"
(boat or caravan) battery today.
Not only would such a battery supply the necessary current with ease, but it
would probably last for a week or two before re-charging according to a prudent
battery maintenance schedule.
This seems a much more satisfactory solution to the problem of powering
Hope-Jones’s organ actions than dry cells.
In fact on the basis of the numbers above, it would be remarkable if they were
used at all despite everything that was said and written at the time.
Note that the internal resistance of the battery was ignored in the foregoing analysis for reasons of simplicity, as it will be in subsequent sections of this article. The same applies to the progressive voltage drop exhibited by dry cells as they discharge. This means that the conclusions arrived at are optimistic, and the actual performance of dry cells in an organ will be even worse in practice than predicted here.
We have noted already that Hope-Jones used
conventional slider chests at the time we are considering.
The evidence suggests he tried operating the sliders in various ways, but one
technique was the use of a double acting electro-pneumatic action: when the stop
was on the slider was pulled one way, and when it was off the slider was pulled
Separate magnets, which we can reasonably presume were similar or identical to
his chest magnets, worked the two actions for each slider.
The evidence in favour of this arrangement
is strengthened because its compatibility with his famous Stop Switch made for a
very simple circuit arrangement.
A circuit mentioned in one of his patents suggests that the stop key for each speaking
stop worked a two-way switch which routed the power to one magnet or the other
of the corresponding slider, and the Stop Switch merely interrupted the common
power line to all these switches when it was operated.
By this means the sliders would remain in whatever position they happened to be
in when the Stop Switch was opened, thereby enabling a new combination to be set
up by manipulating the stop keys.
When the Stop Switch was closed again, current would flow into the slider
magnets corresponding to the new combination which would therefore take
The circuit is shown in Figure 1, which illustrates only five stop circuits for
A Hope-Jones stop action circuit using his “Stop Switch”
Although the circuit described is economical in conception and in components, it is decidedly uneconomical in power consumption. The use of double acting slider actions means that current would have been drawn by all the speaking stops, regardless of whether they were on or off, and for the entire duration that the organ was switched on whether it was actually being played or not. The only exception would have been for the short periods when the Stop Switch was opened. Hope-Jones may have identified this as a problem, as there is evidence that in later instruments he (or other builders to whom he licensed his ideas) developed means for the current to a slider to be shut off once it had moved to its new position in response to a change of registration. However I have been unable to find any evidence at all that such a scheme was used in the Birkenhead organ when its new action was first installed. This is important because it is in the context of this organ that Hope-Jones first made claims for the ability of a dry cell to power his organ actions. Therefore the following analysis proceeds on the assumption that no power-saving measures were employed at St John's, at least in the first instance.
The Birkenhead organ had 35 speaking stops.
It also had a Stop Switch, which means that the circuit described above could
well have been used. If we assume that each slider action used 100 ohm magnets
as considered earlier supplied with 12 volts, the total current drawn
continuously for the speaking stop action alone would be 4.2 A.
If we assume that the organ would have been switched on for at least two hours
each Sunday, corresponding to two services, the required battery capacity per
Sunday would therefore be nearly 8.5 Ah.
This is 8.5 times the capacity required each Sunday for the key action as
Therefore the battery capacity required over a six month period to service the
speaking stops alone would be about 220 Ah.
In the same way as for the key action, we
would have to consider this to be an unrealistically low figure which would need
to be multiplied by a significant factor to become sensible.
However, even if we do not do this, there is no way that a dry battery would
have been able to provide either the standing current of 4.2 A required on a
semi-continuous basis, nor the massive 220 Ah storage capacity.
The story does not stop here because we have yet to consider the couplers. On the Birkenhead organ there were 19 of them (this figure includes the "swell shutters" tab which threw open all the swell shutters and which used a relay similar to those used for coupling). Hope-Jones seems to have tried various coupling techniques but one of them utilised electro-pneumatic multi-contact relays in the organ chamber itself (not in the console). We shall examine this technique here because it would have been more economical in terms of power consumption than coupler relays which used purely electric operation.
Some of the electro-pneumatic coupler relays in the four manual Hope-Jones organ of 1894 at St Paul's, Burton on Trent, now preserved in the Hope-Jones museum of the Lancastrian Theatre Organ Trust in Manchester. This organ was among the first built entirely by the fledgling Hope-Jones Electric Organ Company Ltd, and it appeared only a few years after his famous prototype at St John's, Birkenhead referred to above.
Behind the glass doors are vertical dowels containing metal contact pins. These were rotated by means of cranks attached to the pneumatic motors below, thereby bridging corresponding pairs of contacts which were wired from the rear of the assembly. The pneumatic tubing which actuated the motors can be seen, connected to primary electromagnets of the usual Hope-Jones pattern activated via the stop keys. The mechanism was double-acting, with a second set of motors behind the assembly to return the dowels to their original positions.
(Copyright © Lancastrian Theatre Organ Trust)
The mechanism is illustrated and explained above, and two magnets of the chest type would be required for each electro-pneumatic coupler relay. If this type of relay was used at Birkenhead and if all the couplers were drawn, there would be an additional current drain on the batteries of about 2.3 A assuming no power saving mechanism was incorporated. This would represent an unlikely situation of course, and it is rather difficult to estimate a figure for the power consumed by the couplers because the number of them in use and for what durations would have been dependent on the music being played. However then, as now, it would have been quite normal for a selection of couplers to remain drawn throughout a significant part of a church service, even if the organ was not actually being played, so it is not a factor that can be ignored when estimating the total battery capacity required. In this case however, we have seen already that the speaking stops alone would have ruled out the use of dry cells, so we need go no further.
A section through the multicore cable wired to the electro-pneumatic coupler relays of Hope-Jones's organ at St Paul's, Burton on Trent shown in the previous photo. The diameter of the cable is about 50 mm and the thick common return conductor can be seen in the centre. This was about 8 mm in diameter and was obviously made to have a very low resistance to avoid dropping the voltage significantly under conditions when currents of many ampères might be flowing through it. This is utterly incompatible with an electric action said to have run on a dry cell!
(Copyright © Lancastrian Theatre Organ Trust)
We have seen that a dry battery, though not
a single cell, could just possibly have powered the key action alone of an organ
with electro-pneumatic action provided the organ was small.
However the battery would have run down very quickly, and the life advertised by
Hope-Jones of several months could not have been achieved.
But we then saw that such a battery could not possibly have powered the stop
action of the Birkenhead organ or one of similar size at all, let alone for six
For those who are not yet convinced, we can now move on to consider
Hope-Jones’s combination actions.
The sheer scale of the problem in this case becomes as clear as it is possible
to make it.
In some of his organs the moveable console
was made much of.
At Birkenhead it enabled him to play the organ from outside the church, and at
the McEwan Hall the console could be placed anywhere in the hall.
At the same time these consoles apparently used a combination system in which
the stop tablets were motorised or self-indicating, in other words they moved in
response to the combination pistons (in the form of composition pedals and
“compound composition keys” similar to elaborate thumb pistons).
Because of the moveable console, the combination action must have been purely
electric rather than electro-pneumatic or pneumatic.
It would not have been practical to supply wind to a moveable console which was
on the end of an electric cable 100 feet or more in length unless it had a small
blower and reservoir within.
But what would have powered the blower, we can ask rhetorically?
A dry battery? Surely, therefore, we are entitled to discount pneumatic assistance to the
The amount of power required to move stop keys purely electrically is considerable. In order to achieve a smart action together with enough force to overcome the toggle spring in the stop unit, an electromagnet is required which typically consumes 0.5 A and has 1000 - 2000 turns of wire. These figures are representative of modern practice. The consequential resistance of such a coil demands the use of at least 12 volts to achieve the necessary current. Moving many stops on or off simultaneously, as will occur when a combination piston is operated, therefore means that a power supply capable of delivering several tens of ampères at 12 – 15 volts is required. For the organ to function satisfactorily this power demand would need to be satisfied over periods of at least a few weeks of normal playing. Dry cells could not possibly do this, even today. As well as the problems of insufficient stored energy and fatigue, the internal resistance of dry cells sets a limit to the maximum current which can be drawn and this will often be less than the current necessary to operate the stop magnets.
Today it is easy to forget that over a
hundred years ago providing power for an electric combination action was far
from a trivial problem.
On the contrary, it was a major engineering challenge, illustrated by persistent
problems associated with such actions until well into the 20th
For example, the instantaneous response of the stop keys on Wurlitzer theatre
organs was because they were operated electro-pneumatically, unlike the fully
electric ones on those of their competitors which sometimes fluttered annoyingly
in response to the pistons, or refused to move at all.
The limited range of mobility in theatre consoles meant that it was not
difficult to supply wind as necessary. Therefore, although Hope-Jones could have
used an electro-pneumatic technique in his fixed consoles, it would have been
near impossible with his fully mobile ones as noted above.
Therefore we are led to assume his combination action was purely electric.
For the reasons mentioned above the necessary current could not possibly
have been supplied by dry cells; even large ones would have expired in a matter
of seconds after a few attempts to use the pistons.
Thus it demanded the use of substantial accumulators or other techniques which
are considered later.
There is certainly no place for dry cells in a detached console of the
Hope-Jones type, and therefore their mention in connection with the McEwan Hall
and other organs gives rise to doubts about the veracity of the statements.
While they could perhaps have been used to power the key action for very limited
periods – just – it is untrue that they could have powered a motorised
The notion of a single dry cell in these circumstances is even more
The marmalade jar statement – that a single dry cell could have powered a four
manual organ at all, let alone for six months – can be dismissed as nonsense.
Power - Ancient and Modern
Shown left is a lead-acid accumulator from the 1920's. This delivered 2 volts with various storage capacities related to physical size, 20 Ah being a typical middle of the range figure. The accumulators available to Hope-Jones would have been similar to this, although they benefited from subsequent development particularly during the first world war. A battery of 4 to 6 suitably sized cells connected in series would have powered the actions of his organs reliably for a week or two before recharging.
On the right is an electronically stabilised organ power supply of the type which was introduced by several supply houses in the 1970's. This one could deliver 20 A at a rock-steady voltage of 15 to 20 volts, chosen by the organ builder. It took the best part of 100 years to get to this level of sophistication.
If we were to be limited to battery power, the obvious 19th century answer to the power supply question had to be re-chargeable lead-acid accumulators rather than dry cells or any other form of primary battery. Because they can be recharged, accumulators are known as secondary cells. They also possess several other desirable characteristics - their internal resistance is negligible thus they can supply as much current as necessary, they do not suffer from short term fatigue, they provide a usefully higher voltage (2 volts compared to 1.5) and they can be obtained in a variety of sizes related to the amount of energy stored (capacities well over 100 Ah are normal). The accumulators available to Hope-Jones would have had all these characteristics.
Moreover, Hope-Jones was no stranger to them because he had been a senior telephone engineer and a naval “electrician”. Telephone exchanges were full of relays and magnets just like organs, and they required large currents at low voltage at a time when the demand for telephones was continually increasing and because current-hungry techniques such as automatic dialling were being developed. Typically the DC power in an exchange would either have been derived from the mains via a motor-generator set, or from a dynamo driven by some form of engine. In both cases the voltage would have been stabilised by lead-acid accumulators. The battery rooms of Strowger-switched telephone exchanges which still existed in some districts of the UK as late as the 1980’s would have looked entirely familiar to Hope-Jones. Accumulators were also widely used in ships, for example to provide standby power, and the first electrically powered submarines using enormous cells had already been built by the time Hope-Jones had completed his Birkenhead organ.
Against this background what could be more natural than for Hope-Jones to use the same system for his organs? In favourable circumstances the accumulators might have been kept charged using a low voltage DC dynamo driven from the blowing gear, or (less frequently) rotary motor-generators connected to the mains if available. Otherwise they would simply have had to be re-charged regularly by taking them to a local garage or blacksmith’s, for example. But because there is less of a requirement to stabilise the voltage in an organ than in a telephone system, the expensive and inconvenient storage accumulators could have been omitted when the other forms of power were available.
The blowing plant of a Christie (Hill, Norman & Beard) theatre organ c. 1930. I am unsure of the actual instrument, but it was possibly Reginald Foort's organ at the Regal cinema, Marble Arch, London. The low voltage dynamo for the action current is indicated by the arrow. Belt-driven from the motor shaft, it was similar in size to the type of heavy duty dynamo then used in the posher cars (definitely not your Austin 7 or Ford 8!), and like them, it delivered about 12 volts DC at currents up to several tens of ampères. Robert Hope-Jones used similar dynamos from the outset whenever he could, from the 1890's onwards, thereby initiating a trend which ensured that they remained in universal use worldwide until solid state transformer-rectifier sets began to displace them in the mid-20th century. Dry cells my eye!
Hope-Jones did consider the use of dynamos because they are mentioned in his surviving notebooks. Therefore it would be surprising if he did not actually use them in his organs. Such a dynamo could easily have been driven by the town gas engine which was used to blow the Birkenhead organ, one of those whose action was supposed to have been operated by dry cells, and in fact this was the case. He wrote papers in the open literature which prove it, should there be any doubt. It is possible the engine in question was one of many made by Bisschop and used for organ blowing purposes, a surviving example of which can be seen in the Museum of Science and Industry at nearby Manchester (illustrated below).
A Bisschop town gas engine of 1882 (Museum of Science and Industry in Manchester). This delivered "1.5 man power" and could be "managed by any boy or girl". A chilling echo of those dark, Satanic mills. Note the dual belt-drive pulleys, one of which could have been used to drive a low voltage dynamo as at St John's, Birkenhead, while the other worked the bellows crank. It is believed this is the only surviving example of a Victorian gas engine, and it was still in service in the mid-twentieth century working a large wood turning lathe for the production of wooden mangle rollers. Those unfamiliar with mangles will need to know they were hand operated machines used for squeezing water out of newly washed garments prior to hanging them out to dry.
If the Birkenhead organ had a gas engine and a dynamo, which it did, why did Hope-Jones claim that its action ran on a dry cell? And why have people believed him for so long?
For those who continue to doubt or ignore this evidence, these hypotheses are nevertheless supported by collateral information such as the following. The console of the 1896 Hope-Jones organ at Worcester Cathedral had a voltmeter, quaintly called a galvanometer in some contemporary references, which possibly (we might go so far as to say probably) indicated the voltage given by a dynamo or motor-generator. As if to speak of his previous shipyard connections, it was of polished brass and of enormous ships’-engine-room dimensions, as can be seen from the picture below. Action voltmeters (smaller ones) were standard console equipment in electric action organs for much of the 20th century and are not unknown today. In addition two large starter rheostats were present at the Worcester console, also visible in the picture, confirming that mains powered blowing was used as mentioned in some contemporary material. Thus a dynamo for the action current could have been driven by a blower motor, or perhaps one of the rheostats operated a motor-generator.
Some of the electrical gubbins associated with the Hope-Jones organ at Worcester cathedral c. 1896, attached to the stonework to the right of the console. The box at the top indicated how much air was in the reservoir(s), and in the original photograph it is just possible to discern the word 'EMPTY' displayed in the window. Therefore the wind was switched off when this picture was taken. I am unsure whether this indicator was operated pneumatically or electrically however, as the connection leading from it could either have been a small diameter rubber tube or an electrical cable. Below it is the enormous brass action voltmeter referred to in the text, probably made by the firm of Evershed & Vignoles, and below that can be seen the two quadrant starter rheostats also mentioned. These would have become hot while starting the organ, so the organists were taking a chance in allowing their music books to spill over into this area. At the bottom of the picture can be seen some Victorian electrical fittings (two pin plugs, sockets and fuses) made of porcelain. (Reproduced by permission of the Dean and Chapter of Worcester).
The rather impressive console itself can be seen in the article Elgar's Organ Sonata and the Organs of Worcester Cathedral elsewhere on this website.
After reviewing material such as this, can anyone really continue to believe that Hope-Jones's largest organs actually ran on a single dry cell?
I also examined the small Hope-Jones organ at Pilton in Devon some years ago when some of its builder’s handiwork was still discernible. A fascinating aspect of this encounter was to discover that some villagers could remember the need to re-charge the action accumulators of the organ at the local garage as late as the 1920’s. The need for this was because the church was lit by gas when the organ was installed in 1898, and the UK National Grid was not operational until the 1930’s. Accounts from the time are unambiguous that the organ had an all-electric moveable console when first installed, including a Stop Switch, combination pistons and motorised tilting tablets. Therefore it seems certain that its action was so powered; from an engineering viewpoint no other conclusion makes sense. So if a small two manual instrument in the depths of rural Devon used accumulators, it is inconceivable that its monstrous and famous relative at Worcester would have made do with dry cells even assuming there were no insuperable engineering objections to their use.
Finally, all accounts of those
player-pianos which used electric action describe the use of accumulators when
power from the mains was unavailable.
No mention of dry batteries appears to exist.
These instruments were developed around the time we are speaking of here, and
some of them used an action whose power requirement would have been similar to
that of a Hope-Jones organ.
There was much cross-fertilisation between organ and player-piano actions of
both the pneumatic and electric varieties around the end of the 19th
What were other builders of electric action
organs doing in the closing decade of the 19th century?
It seems from his own accounts that Lewis struggled for a time with “Le Clanché”
If this is true they would have been even more inconvenient than dry cells
because they were “wet”, although it is possible that the terms “dry
cell” and “Leclanché cell” were used interchangeably at this time with
little rigour or understanding.
This has no bearing on the arguments here, because both types of cell are
electrically and chemically similar. Notably though, Lewis used a purely
pneumatic combination action which therefore had no implication for the supply
of electrical power, although it would have rendered his consoles more or less
fixed in position.
He also claimed to use magnets with resistances much higher than those used by
However it would not be
surprising if these Lewis actions were not particularly robust or reliable, and
they would have suffered from battery exhaustion and fatigue problems.
These could only have been prevented by the most meticulous attention to battery
replacement (not re-charging, as Leclanché cells cannot be re-charged).
Binns was trying to use dry cells,
apparently on the advice of “a celebrated Electrician”.
This firm also claimed that “perfect success is guaranteed”, an example of
the complacency and arrogance of some of their marketing material at this time
which was breathtaking.
The errors and blatant falsehoods it contained suggests strongly it was written
before they had made a single successful action.
Walker’s were more sensible; they used
accumulators together with an electro-pneumatic combination action for the draw
Thus only limited demands were made on the batteries when pistons were used, and
ample current would have been available to work the key action for relatively
As with Lewis though, the consoles would not have been moveable to the extent
possible with those of Hope-Jones.
It was probably Hill which exhibited the
best and most professional engineering approach in organ after organ.
This firm would have nothing to do with primary cells of any type, and they used
accumulators which were charged from dynamos, motor-generators or transformers
when the circumstances permitted.
(Their use of the word “transformer” probably meant a rotary motor-generator
capable of transforming DC mains voltages, rather than the AC-only device
implied by today’s usage).
Some evidence suggests the storage capacity of the accumulators was well in
excess of 100 Ah, which not only accords with the analysis earlier in
this article but shows that the firm had access to excellent engineering advice.
The dynamos were driven by the blowing engines in some cases.
In practice Hope-Jones was using much the
same techniques as Hill.
The difference is that one was open and honest about it and the other,
apparently, was less so.
Hope-Jones could not have employed a single
dry cell in his organs because their use would have raised insurmountable
To understand why he apparently said or implied otherwise, it is useful to
recall some of the realities of the times.
The end of the 19th century can
euphemistically be described as an era of robust commercialism.
There was no Advertising Standards Authority and no Trades Descriptions or Sales
of Goods legislation.
Caveat emptor was an accepted rule of the day.
It was quick and relatively inexpensive to obtain patent after patent, not just
to protect one’s ideas but to use the patent system as a means of propagating
Even “respectable” journals would print scurrilous noise from anonymous
correspondents if it was deemed good for circulation.
Moreover, few understood anything at all about electricity beyond those who had
made it their profession, and the majority of the population was suspicious of
it. While some might have known about dry
cells, almost none would have heard of accumulators and even fewer would have
understood the difference between primary and secondary cells. Therefore the temptation for an entrepreneurial innovator to deliberately lead
his competitors up a blind alley and to hoodwink potential customers must have
been difficult to resist. Whether or not Hope-Jones acted in this way, he was
certainly not the only one.
Organ builders even today sometimes lapse in these matters: an organ advertised
in the 1990’s as the largest mechanical action organ in the UK would not work
were it not for electrical assistance over much of the compass.
A century ago such diseases were endemic.
The association of dry cells with
Hope-Jones is so strong that one is entitled at least to examine his motives and
integrity when, as a professional engineer, he must have known that they were
the worst possible way to go.
It seems fairly clear that Binns and to a lesser extent Lewis swallowed the
bait, presumably before realising they had made expensive mistakes.
Hill quite obviously did not, and their electro-pneumatic actions seemed to be
models of fine engineering from an early date.
Perhaps a lesson arising from this story is
that those who have denounced Hope-Jones so loudly for over a century have
merely demonstrated that the abandonment of scholarship allows myths to flourish
which could have been dismissed almost before they arose.
Hope-Jones did not use dry cells, and
certainly not a single cell, to power the action of his organ at St John's,
Birkenhead, because he could not
have done. The instrument would not have worked at all. As far as
his later organs were concerned, and depending on their design (e.g. whether
they had an electric or an electro-pneumatic stop combination system), these too would
either have not worked at all or they would have ceased to work after an
inconveniently short time if dry cells had been used. In no case could a
single cell have been used. Far from designing his electrical system to run on minimal power as the
contemporary literature would have us believe, in reality and quite obviously he
was completely unconcerned about the implications for power consumption.
One only has to consider a few of the ways in which his Stop Switch, sforzando,
double touch, transposing and stop combination circuits might have worked, for
example, to realise how he casually multiplied the number of relays and magnets
in his organs until they did indeed resemble ersatz telephone exchanges.
We have seen that even while music was not actually being played, many of these
would be consuming current as long as the St John's organ was switched on.
In no way can that approach be considered economical in power consumption terms.
In no way could any engineer even today make a similar system using 1890’s
technology and have it run on a dry cell for months on end; simple
arithmetic using Ohm’s Law would defeat him at the design stage.
It is only because Hope-Jones was confident in his ability to supply as much
current as necessary that these matters were of no concern to him.
At the same time he was also correct in his
belief that few others possessed such knowledge.
But instead of that being sufficient in itself to give him a head start in these
areas, the evidence that his competitors and the public at large were deceived
by a deliberate misinformation campaign seems overwhelming.
The successes of this campaign reverberate to the present day:
as recently as the late 1990’s a historian (Stephen Bicknell) wrote “by using the combined
armature/valve electro-magnet he [Hope-Jones] was able to use low voltages and
reduced the current consumption of the organ to manageable proportions, opening
the way to a solution to the battery problem”. And, sadly, some of today's well known
organ builders are apparently taken in - John
Norman has written that Hope-Jones "demonstrated that on his
system a large four-manual instrument needed only the energy in a tiny 4 1/2
volt pocket torch dry battery". Yet the Hope-Jones action magnet was probably of lower resistance than those of
any of his competitors (see the Appendices), thus it consumed more, not less, current
for a given voltage.
Nor would it have worked on very low voltages such as that produced by a dry
cell, particularly with the wind pressures he used.
Therefore this argument is demolished even before considering all the ancillary
functionality of his organs, in particular their stop and combination actions.
There was no “battery problem” for Hope-Jones because he did not rely on
His thinking and practice had moved way beyond the horizons of his time and
beyond the vision of some today.
Reminding ourselves of his position, he
would have wanted to assure his potential customers living in areas away from
mains electricity (i.e. the majority) that his organs would not suffer from
batteries running down as did those of his competitors.
But to emphasise that it would have been necessary to re-charge accumulators,
which he assuredly did use, would have been commercial suicide.
It would have demonstrated that his actions were in reality no different to
anyone else’s in this regard.
Moreover, most people would have had no idea about the difference between
primary and secondary batteries and some might even have tried to substitute dry
batteries in their Hope-Jones organ because of a belief “they would not need
The consequences would have been disastrous.
All these awkward difficulties would have been avoidable by specifically not
referring to accumulators and their need for re-charging, and instead relying on
vague references to dry cells which people would have recognised as being
available at their local hardware shop.
This was quite obviously backed up by flaunting an action magnet which allegedly
consumed a minute amount of electricity, simply because its armature was smaller
than any that had been used hitherto.
The claim about the armature was true but that concerning the amount of current
consumed was quite false, but few would have had the insight to realise it.
No doubt there are those who will prefer a
different interpretation of the facts, and will seize on the inability of dry
cells to energise Hope-Jones’s actions to explain why they were “so
However it is only necessary to reply that this brings us face to face with
another myth. By and large his organs worked and they were not intrinsically
unreliable, provided the accumulators were kept well charged.
However that is a story for another day.
Whether we are amazed or repelled by Hope-Jones, the facts speak for themselves
if we are prepared to listen to what they are saying.
Thanks are due to several colleagues who included among their number an electro-chemist, a chartered engineer and some organ builders. Among these David Hemsley, the late Brian Wigglesworth and Brian Daniels provided much useful feedback and other assistance during the preparation of this article. I am also grateful to Peter Blackett for drawing my attention to the advertisement for Exide batteries, and to the Dean and Chapter of Worcester for permission to reproduce photographic material relating to their former Hope-Jones organ.
I should also like to mention the friendly assistance and information provided by Don Hyde and Roger C Fisher of the Lancastrian Theatre Organ Trust, whose Hope-Jones museum will be of particular interest to many readers of this article.
Because we are considering Hope-Jones, it might have been appropriate to have used his own illustration of a chest magnet contained in one of his patents (number 15461 of 1890). Unfortunately the drawings from those days are scrappy, they do not reproduce well and they also contain evidence of the misinformation tactics associated with Hope-Jones. This is particularly true of the diagram illustrating his chest magnet, but an attempt has been made here to re-draw it along the lines and to the scale depicted in the patent (Figure A1-1). However in doing this, no attempt was made to add details which might have been omitted in the original; these included no device such as a leaf spring to assist the return of the disc against gravity (though this might not have been necessary), no indication of how the disc formed an airtight seal when the magnet was energised and no means of support for the electromagnet itself. Moreover, since the disc armature as depicted in the patent would have rested on the magnet poles when the organ was not in use, this meant that all the pallets of the organ could have opened for a short time when the organ was turned on. This is because wind pressure appears to be the sole agent in raising the armature against gravity. This would have been an undesirable characteristic, and it is one of the many features suggesting that there is more to a Hope-Jones patent than meets the eye.
The original Hope-Jones chest magnet ?
A separate diagram in the patent purports
to show that the disc armature covered an exhaust tube perforated with small
holes rather like a miniature pepper pot.
The situation was complicated (deliberately and pointlessly, it seems) by the
holes being depicted as almost microscopic projecting tubules, machined flat so
the valve would be airtight.
If ever there was an example of disingenuousness in a patent this has to be it, because it is difficult to identify any advantage in this arrangement over an ordinary, narrower, tube with an equivalent cross-sectional area. This statement relates to the force which the magnet would have to exert to open the valve against the wind pressure. It stretches credulity to believe someone with the intellect of Hope-Jones would not have realised this, and therefore we have to investigate why he advertised this complication. One possibility concerns the windway of the valve when open, as Hope-Jones apparently maintained that the use of multiple orifices would allow the valve movement to be smaller than would otherwise be necessary to achieve the same air flow. There are grounds for scepticism here however, because of the resistance to air movement through the minute orifices. A more likely reason for the valve as described is that the difficulty and expense of manufacturing such a small item of precision engineering for an average and unsuspecting organ builder would mean that in practice he probably would not have bothered to copy this magnet, thus leaving the field open for exploitation solely by Hope-Jones. Nobody today would dream of using such a fiendish construction for something so basically simple. Another possibility is that the patent might not have been granted without this feature; the patent examiner might otherwise have deemed it too similar to existing “prior art”. This is quite possible given the similar devices in use elsewhere.
Surviving examples suggest the early magnets, both those of Hope-Jones himself and those made by other builders to whom he licensed his designs (such as Norman and Beard) might have included some version or other of the pepper pot. Although I have not come across one myself this does not mean they were never used. But this is irrelevant to the technical argument, which goes as follows: what he was describing here was a magnet whose armature only needed to move a minute amount, therefore by implication it only needed a correspondingly small amount of electrical power. This was erroneous, because the power consumed by the magnet was determined (for a given voltage) solely by its coil resistance. However, some of his organs (particularly those with detached consoles) needed large amounts of power in any case to operate their combination actions. Ergo they could not have worked on dry cells, ergo there was no need to expend effort on a low consumption magnet. Whichever track one follows in tracing a logical path through this patent, one always meets a red herring. Also one should not forget that if the pepper pot had not been included in early magnets Hope-Jones might have exposed himself to possible litigation.
This example illustrates a more general
problem with patents which perhaps is not widely appreciated.
Historians, particularly those without a technical background, need to bear in mind that the patent literature is replete with such
tactics because the degree of protection offered by a patent is not robust.
This remains true today, and anyone who has consulted a patent agent will
Litigation against infringers has frequently ruined patentees even when their
cases were sound.
Therefore the patentee has to build in additional protection for his ideas, and
a good patent agent will tell him how to do it.
Seldom does a well-written patent contain quite enough information to enable an
erstwhile plagiarist to exploit an idea successfully, and often he will be sent
on a wild goose chase in several directions simultaneously. Yet this has
to be done extremely carefully else the patent can be declared invalid if tested
in court. In this and other ways the nice chaps who have since assumed everything
Hope-Jones wrote or said was factual have been oft misled.
Patents are unlike most other pieces of historical documentation because one of
their functions is to mislead within a legal framework.
Understanding the difference between lies and economies with the truth is part
and parcel of drafting a successful patent.
No doubt for the same reason, we find nowhere firm evidence of the resistance of the windings on the original Hope-Jones electromagnet (but see also Appendix 2). Audsley thought it was about 50Ω, though on what basis he came to this conclusion is not recorded. If this was so, the substantial currents required of the batteries and their storage capacities calculated in this article would need to be doubled, making it even more improbable that dry cells could have been used! Although the figure was probably on the low side for the organ at St John's, it probably characterised some later magnets nevertheless. At the other extreme we can estimate what the maximum value might have been by calculating how much wire could have been accommodated on the bobbins of the magnet. Using the dimensions of the magnet in the patent and assuming that insulated copper wire thinner than about 40 SWG would not have been used in 1890, the resistance turns out to be around 110Ω. This is not far away from the values typically found in today’s components. Some of Hope-Jones's allegedly original chest magnets are said to be still around, leading some to make measurements of their parameters and performance. However such data need to be treated with circumspection : some drawings suggest the original magnet at St John's was probably not made in "monobloc" form but as part of an assembly of several held together within a wooden framework which also included the primary pneumatic motors and valves. Moreover, the frequency with which Hope-Jones's actions were rebuilt, and the short time which often elapsed before the first rebuild took place, means that many original action components would have been consigned to undocumented history well before the 1920's. Even some otherwise genuine surviving magnets may have been rewound to enable them to work on different voltages, or to overcome the consequences of insulation breakdown and the resultant electrical firework displays which seemed to afflict many Hope-Jones organs (such as those at Worcester cathedral and the McEwan Hall). The insulation may have broken down in some cases because of the failure of the wax impregnation used in some of the magnets. One simply must not jump to conclusions in these areas, and thus it remains a fact that there is now scant evidence of the resistance and winding details used by Hope-Jones for his first magnets in 1889-90. In any case, since he was still experimenting vigorously at this time, it is unlikely that he settled quickly on values for action voltage and magnet resistance which were used unchanged thereafter.
A consequence of the foregoing is that
delusions encouraged by the Hope-Jones chest magnet are still widespread and
Because it contained such a tiny moving part, it is often assumed that it required a
correspondingly tiny amount of electricity to operate it, thereby “solving the
battery problem” of electro-pneumatic actions in the 19th century.
The truth is that stated already: regardless of the size of the moving parts, the
current required by a DC electromagnet for a given voltage is determined solely by the coil
Even at a value around 100Ω, this was far less than that
used by some of Hope-Jones’s competitors, thus his actions would have
exhausted the batteries even more quickly than theirs did.
It is not being over-cynical to say that
probably the correct way to view the Hope-Jones chest magnet patent is to see it
as a successful exercise in misinformation.
The complete absence of data on coil resistance, the incompleteness of the diagrams
and the irrelevance of the pepper pot construction are scarcely coincidental,
thus they all point to this.
We should also remark on the emphasis placed on the minute amount of alleged
armature movement (variously quoted as between 1/100th and 1/64th
of an inch in the Hope-Jones literature, or 0.25 to 0.4 mm), which would be
unnecessarily small in practice.
It all points to an attempt to present the magnet, quite falsely, as one which
consumed a negligible amount of power at a time when the problem of batteries
running down during a church service was causing near-hysteria.
This was undoubtedly a major factor preventing electric actions catching
on, and Hope-Jones was determined to change this because he was pinning his
future career ambitions on it.
In reality his magnet consumed even more
power than those of his competitors, but this could not have been deduced easily
from an examination of the patent.
However power presented no problem for Hope-Jones the professional engineer, and
the ways he actually provided it are described in this article.
Probably the only significant advantage of his magnet was its small size and the
low inertia of its moving parts, making for a more responsive action provided
the pneumatic elements of it were also sufficiently fast.
This was later exploited in the excellent electro-pneumatic actions of Wurlitzer
Without the pepper pot of course, it also became an ideal candidate for high
volume low cost mass production, and so it has remained for over a century.
None of the foregoing should be seen as an attempt to heap yet more opprobrium on Hope-Jones, who has been the target of so much. It is emphasised that nothing in this story is at all out of the ordinary in the patent field, either then or today. Anyone who holds patents will vouch for the lengthy and arcane business of drafting them in association with a professional agent, and for the surprise which some of the accepted tricks of the trade evoke on first acquaintance. It is of course inadvisable to include deliberate untruths as these might invalidate the patent as well as cause other problems, but on the other hand one receives advice about the naivety of being too open! The Hope-Jones magnet patent is an example of how to tread the middle ground successfully.
The Hope-Jones magnet in reality
So what was the original Hope-Jones chest magnet actually like, the one incorporated in the organ at St John's Birkenhead? I do not know for sure, and I doubt there is any hard evidence now available to dispel the uncertainty. However we do have some information about the magnets used a few years later in one of the first organs made entirely by The Hope-Jones Electric Organ Company Ltd for St Paul's church at Burton upon Trent. This organ was installed in 1894, about four years after the Birkenhead instrument was revealed to an astonished world, and it lasted for about 90 years. Parts of it were preserved in the church until recently, when the Lancastrian Theatre Organ Trust removed them to its new Hope-Jones museum in Manchester. Among other items is one of the sound boards still with its array of chest magnets, and this is pictured below.
Action magnets on one of the sound boards of the 1894 Hope-Jones organ at St Paul's, Burton upon Trent.
(Copyright © Lancastrian Theatre Organ Trust)
One of the magnets with its cap removed to reveal the disc armature is shown below:
A Hope-Jones action magnet on the St Paul's, Burton organ with its cap removed.
(Copyright © Lancastrian Theatre Organ Trust)
Unfortunately though, even this evidence does not take us back as far as we would like. At some stage, perhaps as early as 1906, the action was apparently renovated by Norman and Beard. The magnet disc valves were replaced and their seatings modified in some manner. This may mean that the pepper pots, if present, were removed. However the surviving magnets do show that the disc valves moved freely within an array of four guide pins as can be seen above, thus no leaf spring was used. Therefore air pressure was the sole agent in closing the valve to the atmosphere, with the consequential disadvantages mentioned earlier such as all the pallets of the organ trying to open momentarily when the organ was switched on. Whether the ornate fluted brass dust covers seen in the upper picture were part of the original magnets is not known.
The resistance of the coil was about 60 ohms, contrasting with the figure of 100 ohms used for the analysis in this article. The article also used a value of 12 volts for the action voltage, whereas this might also have been lower according to evidence which has come to hand recently. However these variations compensate each other, therefore the figure of 120 mA used in the analysis was probably fairly close to reality in the Birkenhead organ. This means none of the conclusions drawn need to be modified substantially. The Hope-Jones chest magnet was certainly not a particularly low-consumption device as he maintained, and it would have exhausted any form of battery several times quicker than the high resistance magnets used by most of his competitors.
This article has attracted a very large amount of interest since it first appeared in 2003, and it is therefore appropriate to take stock of what has been said and the information which correspondents have offered. Therefore this Appendix is a postscript to the original article.
The span of opinions received was wide. At one extreme was a rejection of virtually everything in the article, to the extent that one correspondent stated his intention to replace the dynamo as the power source for his electro-pneumatic organ with dry cells in an attempt to prove his case and thereby vindicate Hope-Jones (as of mid-2010 I was still waiting to hear the outcome of this experiment). Another continued to deny that Hope-Jones ever made claims that his organs would run on a dry cell, despite the documentary evidence being presented to him repeatedly. These are examples of "don't confuse me with facts, my mind is made up", presumably. On the other hand, much useful data on Hope-Jones's actions were provided, though in some cases it was difficult to separate fact from anecdote and speculation simply on the basis of a few e-mails. One correspondent maintained that the console of the organ at St John's, Birkenhead sported a three-way switch which connected the action either to a dynamo, a set of accumulators or a dry cell. If so, it is interesting to speculate on the circuitry of the hidden connections to the alleged "dry cell" position of the switch. No matter how strenuously people try to persuade themselves and others that the dry cell story was true, they cannot distance themselves from the fact that it was an impossible fiction and that Hope-Jones was therefore unbelievably disingenuous in propagating it.
It is worth saying a few words about "Flag" cells, which several correspondents maintained would be capable of powering an electric action. Until recently these large cells were still available from a few sources (at a price verging on the uneconomic - about £12 each), and they have a volume about half that of the "marmalade jar" size of cell which Hope-Jones claimed would run his organs for six months. They have a quoted storage capacity around 40 Ah but it must be remembered that today they are alkaline cells, not the zinc-carbon type available to Hope-Jones, whose capacities were inferior. In the article it was shown that a capacity many times this value would have been required for the key action alone. Also the 40 Ah figure would only be approached under discharge regimes in which the currents were intermittent and much smaller than those required for a Hope-Jones organ action. In particular these cells would not supply the high peak currents of many ampères required for an electric combination action over a period of several months. Moreover, it has to be remembered that regardless of the size of cell, it is difficult to see how any organ could have worked on the low voltage of 1.5 volts provided by just a single one. When the arguments in the article are applied in this way, any type of dry cell is seen to be inadequate.
The most useful and thought-provoking comments arose from those who have made measurements of the parameters and performance of some components used in Hope-Jones's actions. The resistance of his action magnet and the voltage on which it worked seemed to vary widely. However, when we are considering the use of batteries, the most important parameter is the current drawn because this alone enables a decision to be made whether they could have supplied the peak current demand and the long term energy storage capacity. On the basis of information from several sources, the current required to just move the magnet armature was between 80 to 100 mA in the presence of wind. However, significantly larger currents would have been required in practice for the organ to function reliably. Further evidence of the use of dynamos and accumulators to supply the action current was also provided by these correspondents. No technical support for Hope-Jones's claim that a large organ would work for several months on a single dry cell was forthcoming, thereby confirming the belief that this was nothing more than an advertising scam.
The article was drafted explicitly and from the outset by examining what conclusions could be drawn by applying simple engineering considerations to the design of an electric action, with little or no a priori assumptions about what parameters Hope-Jones actually used. The values chosen for coil resistance and voltage in the study resulted in a current consumption of 120 mA per magnet, some 50% greater than the lower figure of 80 mA quoted above, but not far away from some of the higher values which were quoted. Nevertheless, this implies that the required storage capacity of 80 Ah per cell (to supply the key action alone for a period of six months) derived in the article might have been excessive. However this figure was stated in the article to be conservative, and in practice it would probably need to be multiplied by a considerable factor if an organ was indeed to be powered reliably by batteries for six months. Therefore it is not considered that the conclusions drawn in the article need to be modified.
A noteworthy feature of the correspondence was that nobody, so far, has considered anything beyond the key action alone of the Birkenhead organ. Yet an organ action is a system, a collection of sub-systems of which the key action is but one. Other important sub-systems are the stop and combination actions, and a thrust of the article was to show that dry cells could not have powered these for long periods, if at all. Hope-Jones was a gifted systems engineer, as evidenced by the design and realisation of his extension organs. System-level problems such as those mentioned would not have been lost on him, and because his schemes worked it is obvious that he solved them. It is therefore most unfortunate that he degraded himself and his achievements by uttering, and committing to paper, absurd statements to the effect that a large four manual organ built to his designs would work for six months on a single dry cell.