A Fowler's Gallimaufry (2nd edition, Version 2)
2nd Edition
A Fowler's
Gallimaufry
Peter M. Hopp, CEng MBCS
Version2
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A Fowler’s Gallimaufry
Copyright ©Peter M. Hopp CEng MBCS. 2021
All rights reserved. Including under all international and Pan American Copyright
Conventions. No part of this publication may be displayed , reproduced or transmitted in any
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recording or any other storage and retrieval system now known or to be invented, except by a
reviewer who wishes to quote brief passages in connection with a review written for inclusion
in a magazine, newspaper or broadcast.
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A Fowler’s Gallimaufry
Table of Contents
‘Scientific Publishing’ Pocket-Watch Calculators
The ‘Mechanical Engineer’ (ME) Calculator
Dyson Textile Calculator.
ME Chronology
The Workings of an ME calculator
Other SPC Pocket Watch calculators
Fowler’s Patent Pocket Calculator
Scientific Publishing Type O calculator
Scientific Publishing Textile calculator
Type T Textile Calculator
Fowler’s Type M Textile Calculator
ME Variants
9
10
11
12
13
14
15
16
17
17
19
20
Fowler’s Pocket Watch Calculators
Fowler’s Patents
Fowler’s design changes
Calculator Types
Fowler’s Calculator
Type A
Type A1
Type B Textile
Type E Textile
Type E1 Textile
Type H
Type M Textile
Type O
Type T Textile
Textile Conversion Calculator
Textile (Short Scale) Type
Textile (Long Scale Type) Pick Finding Variety
Textile (Long Scale) Type
Magnum Textile
Fowler’s Textile Calculator
Vest Pocket Calculator MD, H, CSR
Universal Calculator
Universal Blitz Rechner Kurze-Scala
Twelve-Ten Calculator (12-10)
Magnum Long Scale calculator
Jubilee Magnum Extra Long Scale calculator
Nautical Calculator
Artillery Calculator
Long Scale Type R
Long Scale Type RX
Long Scale Calculator
Circular Slide Rule
The Mechanical Engineer (ME)
Junior Calculator
Kearns Machine Time Computer
Mackay Paper & Board Calculator
Ribble Motor services Calculator
Fowler’s Bakelite Cases
24
24
27
28
29
33
34
35
39
40
43
46
47
48
49
51
62
64
65
67
68
69
70
71
73
74
75
77
79
80
83
86
87
88
89
91
92
93
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A Fowler’s Gallimaufry
Major Features of Each Calculator Type
Fowler’s Cases
Fowler as a Manufacturer
Fowler Chronology
Fowler Brief History
Fowler Addresses
Advertising Blocks
Fowler, Father Brief Biographies
Appendix A
Appendix B – Serial Numbers
Appendix C- Fowler Documents
Bibliography
96
99
102
106
108
110
111
114
116
119
136
139
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Acknowledgements
The Cover illustration is taken from the inside page of a Fowler four-page A5 advertising
pamphlet labelled “List 50” which could imply a date of 1950, with a photograph of a Fowler's Long
Scale Calculator on its cover. It advertises that “7 different types are available for all principal
Trades and Industries. Each Calculator is supplied in handsome reinforced case with Instructions.
Price on application.” Elsewhere it describes The MAGNUM Model with a Diam. of Dial 4½" and a
hand added price of 63/-; The UNIVERSAL Model, Diam. of Dial 3⅜" and hand added price of 42/6;
and finally VEST POCKET Model, Diam. of Dial 2⅝" and the same added price of 42/6. It is one of
the few pieces of Fowler advertising I have been able to find. It fascinates me that there are often hand
added changes in ink, Fowler must have had many more than immediately needed documents printed
which then required modification – a sign of a thrifty company?
Within the pages of the book are numerous images of Fowler calculators for which I must thank
the slide rule collecting fraternity for the generosity and help in supplying information to add to the
completeness – such as it is – of the information presented. A resource such as eBay must also be
added as an acknowledgement. Nowhere else is it possible to find such an abundant variety of
calculators to study! The internet generally makes our author’s jobs infinitely easier than ever it was.
I must also thank Alistair Pearson for allowing me to include considerable additional information
relating to textile gauge points and also relevant information on the work and costing of cloth making
that he has researched and generated – thank you Alistair!
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A Fowler’s Gallimaufry
Preface
Fowler’s calculators and their antecedents, those from the Scientific Publishing (SP) stable, have
been written about exhaustively by many authors within the slide rule collecting community, but to
my mind never conclusively. This book attempts to achieve that! It is probably a forlorn hope, but I
would rather travel in hope and nearly achieve my goal than not to travel at all!
I have written several times on these subjects, the “Fowler's Calculators – A Catalogue Raisonné”
by Blankenhorn and de Cesaris in the JOS of Fall 2002 has achieved a degree of acceptance by being
quoted as a knowledgeable source by several eBay sellers. Most recently the SP and Fowler chapters
in my “Pocket-Watch Slide Rules”, Astragal Press 2011 have added to those models recorded.
However, since that date several other articles have added yet further information and data. I beg the
reader’s indulgence for obvious repetition, but the information now will at least be all in one place as
this monograph will attempt to bring it all together!
Why Gallimaufry? Well we have had several articles using the definitive article, and we have had
a Catalogue Raisonné, so I needed to find another and different collective noun to describe a marque,
and I like Gallimaufry, it has a “ring” to it – so there you are!
This also seems the appropriate place to ask that if you the reader come across, or have in your
collection any Fowler's Calculator that does not feature here, please let me have a picture and any
other information about it that you may have – thank you in advance!
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A Fowler’s Gallimaufry
Introduction
My fascination for these quite delightful devices goes back very many years. My attempts at
describing and classifying them are almost as long. My first attempt at describing the genre goes back
to 1998 when, with the assistance of the late John Knott, I produced the first attempt at a “complete
catalogue” of types1. Jenny Wetton of the Museum of Science and Industry in Manchester had
published an article in the Bulletin of the SIS in 19972 which was a pretty short part of a series on
instrument manufacturers in Manchester, and repeated much of what John, who had had preceded me
and her with a short two-page article on the company itself 3, had previously said. These are the first
two articles I have been able to find within the slide rule community.
Anything that purports to describe the Fowler's calculator genre in any conclusive and complete
way must start by describing the Scientific Publishing range as well, for these are the true forefathers
of the Fowler's range, so we will start with the SP calculators.
The de Cesaris and Blankenhorn ‘Catalogue Raisonné’ (from now on called C-R) developed a
numbering system that seems to have found favour with some parts of the slide rule collecting
fraternity. Unfortunately I have not found a sensible way of incorporating the multitude of variants
that are part of both SP and Fowler's manufacture; however I have included the short form reference
from C-R in my later classification. How to include all variants remains a problem. For example we
have 10 variants of SP Mechanical Engineer (which did not feature in the C-R) and 14 of Fowler's
Short Scale Textile (which featured in the C-R as 2MT1 with variants, which were not obvious, from
‘a’ to ‘f’; and were not illustrated). Other models have many variants which similarly were not
included.
Version1: 12.11.2019
Version2: Includes the following:25.01.2021
- Throughout, corrected spelling and grammar errors in Version 1
- New Type A1 calculator
- New Single sided Fowler Calculator (page31)
- Short Scale Textile: further variants identified and included:
o New Type 0 this and the following new Type1a, 4a and 5a were found after examining further
examples.
o New Type 1a
o New Type 3a – as T3 but labelled in English
o New Type 4a – different rear scales inc 2.952.d
o New Type 5a - different rear scales inc 2.952.d
o Variations to later types as well
- New unique Ribble Motor Services Calculator, see page 93
- New Appendix B on Serial numbers
- Fowlers Type B and Fowlers Pick Finding variant – additional gauge point and Textile calculation
information added courtesy of Alistair Pearson
- New Appendix C on Fowler Documents
1
Fowler Pocket-watch Type Calculators, Peter M. Hopp. Journal of the Oughtred Society, Volume 7 No 2, Fall 1998
Scientific Instrument Making in Manchester 1870 – 1940, III: Flatters and Garnet Limited, and Fowler & Company, Jenny Wetton,
Bulletin of the SIS No 53, 1996, p15.
3
Fowler & Company 1898 – 1988, John V. Knott, Journal Of the Oughtred Society Vol 4 No 2, October 1995 p16.
2
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A Fowler’s Gallimaufry
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A Fowler’s Gallimaufry
‘Scientific Publishing’ Pocket-Watch Calculator
Introduction
John Knott 4 and Jenny Wetton 5 have previously covered the history of Fowler, both articles give
the Scientific Publishing Company (SPC) as the root from which Fowler & Co. grew. The range of
‘Fowler’s calculators has also been previously covered6, and pocket-watch type calculators carrying the
SPC name are mentioned. In this document we attempt to define the chronology, and show how the
range started with one pocket-watch calculator, ‘The Mechanical Engineer’, and then expanded via a
small range of SPC calculators to the extensive range of calculators that were later available under the
‘Fowler’ brand name. It is very unlikely that SPC initially manufactured calculators, but we do know
from later information that when they became Fowler they did assemble them.
History
William Henry Fowler set up the Scientific Publishing Company in 1898, his son Harold Fowler
became involved in 1905. SPC were best known for the publication of a range of technical pocketbooks
for architects and the engineering disciplines. William Henry was also the editor of a weekly news
magazine, ‘The Mechanical Engineer’ which was published from 1898, initially at 6d. per week, and
later (by 1909) had reduced to 3d. per week. The availability of a pocket watch calculator from SPC was
advertised during 1898 7. The various Fowler's Pocket Books advertise many different Fowler watch
type calculators over the years. A chronological list of addresses for the Scientific Publishing Company
is as follows:
1898: Corporation St. Manchester, England
1901 - c1915: 53 New Bailey Street, Manchester,
1908: Workshop in the Family home, Sale Lodge, Sale, Cheshire.
Pre 1914: Oakleigh, the Avenue, Sale, Cheshire.
c1915: Fowlers & Co. 53 New Bailey Street, Manchester.
Pocket Watch type calculators
Calculators which are known to have been made or sold under the name of the Scientific Publishing
Company are fairly rare and to date only include the following types:
- The Mechanical Engineer (single scale)
- The Mechanical Engineer (only one version carrying the SPC name) in various sizes
The Mechanical Engineer, desk version (No known examples, but advertised by Halden in
1902)
- Fowler’s Patent Pocket Calculator
- Type T textile calculator
- Type O Calculator – a later version of the Fowler’s patent calculator
We can now look at these in greater detail to establish their chronology and to get a better
understanding of which models were available under the SPC label and when.
Version2
4
5
‘Fowler and Company, 1898 – 1938’; J.V. Knott in Journal of The Oughtred Society, Vol. 4 No 2, Fall 1995, p16-17.
‘Scientific Instrument Making in Manchester, 1870 – 1940’, iii- Flatters and Garner & Fowler and Company; Jenny Wetton in Bulletin
of the Scientific Instrument Society, No 53, (1997), pp 15-18.
‘Fowler's Pocket Watch Type Calculators’; Peter Hopp in Journal of The Oughtred Society, Vol. 7 No 2, Fall 1998, pp 43 - 49.
7
Wetton (above) states ‘In 1898, the ‘Mechanical Engineer’ carried an article on a circular calculator, under the same name, which had
been developed by the proprietors’. She goes on to say ‘Records do not show who designed this instrument or where it was made; it was
sold via the Scientific Publishing Co.’. See Appendix A.
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A Fowler’s Gallimaufry
Figure 1.1: 1.1a, 1.1b, 1.1c, and 1.1d ‘Mechanical Engineer’ calculators various
The ‘Mechanical Engineer’ (ME) Calculator
There has been some speculation as to who made the ‘ME’ calculator. A previous article 8, identified
the apparent anomaly of a ‘Swiss’ marking on some examples, though the majority of known examples
show no obvious maker’s name. However we have now found enough examples which do carry a
‘maker's name’ i.e. Scientific Publishing or ‘The Mechanical Engineer’ so that we can now be certain that
SPC were the retailer if not the actual maker. Four examples are shown in Figure 1.1; this appears to
cover all known major variants with multi scales. Here we have an example with no maker's name and
no model name (1.1a), a second example marked ‘The Mechanical Engineer’ but no makers name (1.1b),
a third marked ‘Scientific Publishing Company, Manchester’ (1.1c), and finally one marked ‘The
Mechanical Engineer Price 6d. weekly’ (1.1d). While many SPC adverts state that the calculator was
available in two sizes, we now know that they actually came in three sizes, the scale diameters of 1¾", 2"
and 2½" being obvious from Figure 1.1. The chronology of the models is more difficult to ascertain, and
there are more and different variants as will be demonstrated later.
Subsequently we have also found what
appears to be a ‘single scale’ Mechanical
Engineer pocket calculator, a device that only
carries the second scale of the ‘normal’ ME, i.e.
the ‘calculating scale’ of the ME. Why SPC
should decide to make such a simple calculator,
and when, is not known, but we can try some
theories and see how they work out.
Image Courtesy of the Conrad Schure Collection
Figure 1.2: Single scale ME
The device has 2" (51 mm) diameter scales
in a 2½" (62 mm) diameter single sided case
8
‘The Mechanical Engineer’; Bob De Cesaris in Journal of The Oughtred Society, Vol. 7 No 1, Spring 1998, pp 23 - 24.
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A Fowler’s Gallimaufry
and carries all the other characteristics of an ME, including the furniture etc., and it also carries the
clearest Scientific Publishing Co., Manchester; labeling. As with the ME, the crown turns the scale and
the side knob the pointer.
Note also that a 1902 Halden catalog advertises a desk version of a Mechanical Engineer. There is
neither description nor illustration, but it is priced the same as an F-C Calculigraphe with a nickel case.
This is a curious device as it has not been seen
advertised anywhere else, and no examples are known.
With this 9 and other evidence ([4] and [5]) we can
now be sure that the ME was sold by the SPC, and is in
all probability the earliest design made and sold by
them starting from 1898. Exactly what ‘made’ entailed
is still open to debate. We know from contemporary
photographs (c1908) in the Bolton Museum that
Fowler assembled pocket-watch calculators (see the
later Fowler sections). From this we can assume that
either he had the components made to his designs, or
that he bought off-the-shelf (pocket-watch?)
components from any of a variety of sources; and
hence some could have been ‘Swiss’. Note that the
calculator in Figure 1.1d has ‘Swiss’ stamped into the
axle, (see also Figure 1.16) and Figure 1.3 is marked
‘Swiss Make’ on the dial. We do not know what this
link was.
Figure 1.3: ME marked “Swiss Make” on the dial
Figure 1.1 appears to cover all known variants of the multi-scale ME, and Figure 1.2 is yet another in
their range of calculators, the single scale calculator.
Dyson Textile Calculator.
The Dyson Textile calculator very much appears to
have been made by SP, though there is nothing stated on
the device to confirm this. It has most of the “family
features” of the ME and so it is being included here.
Whether it is a variant of the ME, or whether it is another
type of SP calculator remains unknown. Observing the
internal mechanism of the Dyson and comparing it with the
ME might confirm or otherwise this supposition.
It is included in the story at this point as the calculator
follows the ME pattern by being in a pocket-watch case,
and not the later ‘Fowler’ patent patterns.
The scales on the Dyson are as follows:
Centered on the index of the complete outer scale
Figure 1.4: Dyson Textile calculator
9
‘Subtract 20, 10, 1 10, 20, 30, Add’. The complete outer
scale is a logarithmic single cycle scale in 10’s decimally
‘Scientific Instrument Making in Manchester, 1870 – 1940’, iii- Flatters and Garner & Fowler and Company; Jenny Wetton in Bulletin of
the Scientific Instrument Society, No 53, (1997), pp 15-18.
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A Fowler’s Gallimaufry
divided, followed inwards by a scale in Shillings and old pence from 1/- to 20/- divided logarithmically
and Centered on 8/4d (why?) with finally another single cycle log scale from 1 to 10 in quarters.
ME Chronology
Figure 1.5: 1901 SP advert
Figure 1.6: 1909 SP advert
SPC made three sizes of ME. If we take the SPC adverts at face value, i.e. that there were two sizes
of calculator available at any one time, but with the caveat that this might have been any two sizes at one
time, then we can possibly estimate a chronology. The 1901 edition of ‘Fowler’s Mechanical Engineers
Pocket Book’ carries an advert (Figure 1.5) which shows a calculator marked ‘The Mechanical Engineer’
and gives prices for the 1¾" and 2½" scale diameter sizes available. Pickworth [5] shows the same advert
and an ‘early’ (undated) edition of ‘Watch Calculator’ [4] shows the same two sizes with the same
markings. A ‘later’ edition of [4] (also undated) shows a small (1¾") calculator marked as described
earlier, and a larger (2") calculator marked ‘Scientific Publishing Co, Manchester’. The 1909 edition of
‘Fowler’s Mechanical Engineers Pocket Book’ carries an advert (Figure 1.6) which shows only one size
of calculator, the 2" version, marked SPC, Manchester, and priced the same as the smaller version in the
1901 advert. The 1908 issue of ‘Calvert’s Mechanics’ Almanac’ (typeset in 1907) also carries the same
advert, hence we can estimate 1907 as a possible earliest date for the advent of the SCP marked 2"
models.
The ‘no name’ version of the 1¾" ME remains an enigma. Were they intended to be sold by
independent retailers in parallel with the marked versions, or were they the earliest (or latest) version
available? We do not know. Hopefully future evidence will answer the question.
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A Fowler’s Gallimaufry
From the evidence above it is possible to estimate a chronology for the ME:
- No name (Fig 1.1a) 1¾" diam.
- ‘Mech Eng’ (Fig 1.1b) 1¾" diam.
- ‘Mech Eng 6d.’ (Fig 1.1d) 2½" diam.
- SPC (Fig 1.1c) 2" diam.
1898 - 1900 (assuming that they were the earliest
model)
1900 - 1907 (Pickworth etc. adverts all show
calculators marked ME)
1900 - 1907 (or possibly earlier)
1907 - 1910
Note that the ‘No Name’ versions may have been produced throughout their history for other
retailers to sell; they are not uncommon. By not carrying any marking they have caused confusion as
to what the device is, and others (see ‘Davis’ in the listing of all variants later in this section) have
engraved the back of the calculator, or named them in some other way.
Note that a more complete expose of the many variants of Mechanical Engineer types is included
later as a separate section.
The Workings of an ME calculator
With many thanks to Peter Fox, the following suite
of illustrations gives us a great look at how these
calculators were assembled. The final picture of the
mechanism complete with axles, ready for fitting also
solves another of life’s rich mysteries – how these can be
taken to bits or re-assembled. The spring, accessed via
the circular holes in the plate, which allows the axles to
be removed to allow the plate to be removed is sheer
brilliance!
Figure 1.7: The Workings of an ME calculator
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A Fowler’s Gallimaufry
Other SPC Pocket Watch calculators
Having established that SPC started with the Mechanical Engineer as their first design, and that at
least one model was produced with SPC as the ‘makers name’, what calculators followed the ME and
when? The intermediate chronology is not obvious; however we can also be fairly definite about the
calculator which superseded the ME. This has to be Fowler’s Patent Pocket Calculator, patented in 1910.
This also became the Type ‘O’ later, still under the SPC name.
There can be little argument that any calculator with the very obvious centre button on the obverse
must be the model that followed on from the ME and started the Fowler calculator dynasty. Initially it
was thought that only the Patent Pocket Calculator, and a Textile Calculator with the back-button existed,
but subsequently a Fowler Type E1 with the single back button has been found.
Figure 1.8: 1913 SP advert for the 1910 Patent Calculator
Figure 1.9: Fowler's Patent Calculator by SPC
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A Fowler’s Gallimaufry
Fowler’s Patent Pocket Calculator.
2AG1
The 1910 date of Patent 5,528 granted to W.H. Fowler gives a very strong indication that this was the
next chronological design following the ME, which in all probability it superseded. The patent covers the
very characteristic and unique calculator with centre button on the obverse driving the pointer, and the
scale driven from the single crown. It was advertised in the 1913 Fowler’s Electrical Engineers Pocket
Handbook, see Figure 1.8.
Figure 1.10: Fowlers Patent Calculator by SPC
Figure 1.9 shows an example of Fowler’s Patent Calculator marked Scientific Publishing Ltd. It is
not clear whether this particular example with its three clips is a home-made addition to stop the
glasses falling out of the cast case, or whether these were part of the original fit. I believe that they are
a home-made cure for a problem. A second example shown in Figure 1.10 does not have the clips.
All three clips on the example are very similar leading to the suggestion that they might have been
available as a DIY, or a “fix” by a previous owner as a cure for the problem.
We also have an example of an early type of Textile calculator and its later evolution under the
SPC name; we do not think that any other models also existed during this time.
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A Fowler’s Gallimaufry
Scientific Publishing Type O calculator
2BG1
Figure 1.11: Scientific Publishing Type 'O' calculator (The Patent Pocket Calculator)
(The original illustration was taken from C-R; I had not seen another. Since then the above
example appeared in the Tom Wyman collection; it is rare!)
A later version with two crowns instead of the Centre button is called a SP Type ‘O’, this being
printed where the Centre button used to be. (See Figure 1.11.) This is the first evolution from the
Patent Calculator. An example of the next evolution, another of what became the more usual twocrown device (known as the Type H) made by Fowler & Co. which is covered by patent 20,416 of
1912 by W.H. & H. Fowler, has a date of ‘11.11.1915’ written inside it. It is accompanied by an SPC
instruction manual which is for the earlier style of calculator with Centre button, but has a stuck-in
overprint to the effect that the scales: ‘… are rotated by a nut at the side instead of a button at the
Centre, but this does not affect the instructions for making the calculations’. This calculator, the Type
H, was still being advertised in the 1925 Fowler’s Mechanic’s and Machinist’s Pocket Book. This is
further evidence that by 1915 SPC had definitely become Fowler & Co. and was producing pocketwatch calculators under that name rather than SPC, and we can now be sure that the SPC model of the
Patent Calculator was made and sold from 1910 through to 1914 or 1915.
Later patents, 3,638/1914 and 15,990/1914, cover anti-backlash mechanisms and a calculator
which does not use crowns at all but is rather more like Halden’s Calculex utilizing thumb nuts on
both sides, it was probably never manufactured. These patents were at the very end of the SPC
period.
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A Fowler’s Gallimaufry
Scientific Publishing Textile calculator
2AT1
This is a variant of the Patent Calculator complete with the Centre button, Scientific Publishing
name, and tables on the rear that would soon turn into the slightly later Type T with its side key as
shown below (Figure 1.13). The “Instructions for Working Fowler’s Patent Textile Calculator with
Uniform List of Prices” that accompanies such a calculator in the author’s collection includes various
printed notes relating to prices dated, July 1907, February 1909 and January 1911. This allows us to
assume that they date from at least 1911 and as the Patent Pocket Calculator is advertised in the back
of the instructions, we know they are contemporaneous.
Figure 1.12: Scientific Publishing Textile Calculator
Type T Textile Calculator
2BT1
The Type T Textile calculator is shown below (Figures 1.13 and 1.14). Apart from carrying the
Scientific Publishing Co maker's name, it is very obviously from the same period characterized by the
very thin pointer, the prominent axle, and the cast metal case with the two spokes carrying the
mechanism. Note that the anti-backlash mechanism shown in Figures 1.14 and 1.15 is covered by
patent 3,638/1914 from which we can more accurately deduce that the change from SPC to Fowler
took place around the time of the patent grant (May 1914). This Type T textile calculator is thus from
very late in the SPC period (c1913?). When they started making Type T Textile calculators is not
known, however the general style would evolve for years to come as part of the ‘Fowler’ range, see
the next chapter. I am not aware of a Type T calculator in the ‘Fowler’ range.
It is believed that with the single exception of the lone Fowler's E1 shown later, all back-button
calculators produced carried the Scientific Publishing Co maker’s name. It is also believed that each
back-button design was replaced with a similar design but with the later side-winder, and now carried
a Type number, but still with the SP maker’s name:
Fowler Patent Calculator → Fowler's Calculator Type O
Fowler's Textile Calculator → Fowler's Textile Calculator Type T
The SP Fowler's Textile Type T was then replaced by a Fowler's Textile Type M with Fowler as
the maker.
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A Fowler’s Gallimaufry
Figure 1.13: Scientific Publishing Type T Textile Calculator
Figure 1.14: Type T Textile Calculator with yellow lens and showing mechanism
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A Fowler’s Gallimaufry
Fowler’s Type M Textile Calculator
Not Mentioned
This Fowler’s calculator has been included in the Scientific Publishing section to give an
indication of when Scientific Publishing ceased to exist as a ‘maker’. An example of this calculator
dated late 1914 is shown in Figure 1.15. The style of this device and the mechanism is extremely
similar to the earlier Type T (Figure 1.13) and other SPC calculators. However, this Type M carries
the Fowler & Co. name, and it is the first time we see the table of Weft, Looms and Reeds that would
become ubiquitous across many Fowler Textile calculators. The pencil annotation on the back of the
scale says ‘Repd. 6/12/1914. HF’. Was this calculator repaired by Harold Fowler himself? Probably,
but we will never know. However this is further evidence that no later than December 1914 and
probably slightly earlier as this was a repair to a ‘Fowler’ calculator, SPC had become Fowler & Co.,
Manchester.
Figure 1.15, a, b, and c: Fowler & Co Type M Textile Calculator
This is certainly one of the first, if not the first calculator, to carry the Fowler label.
Summary
We can now conclude that the ME was the first pocket-watch calculator made (or at least
assembled) by The Scientific Publishing Company, and that it
was made from 1898 and continued to be made in various guises
until 1910 when the patent for Fowler’s Patent Calculator was
taken out, and SPC started to manufacture the Fowler's Patent
calculator instead. The Patent Pocket Calculator with the Centre
button was made and sold under the SPC name from 1910 until
about 1914, and then evolved to have two crowns (one crown
and one side-winder) when it was sold under the Fowler name.
Whether the two-crown version was made with the SPC name is
not known. We can reliably speculate as to the chronology of the
SPC Type T textile calculator and for how long it was made,
however there is no hard evidence available to date it.
Figure 1.16: ME marked "Swiss" on
the axle
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Other calculators carrying the Scientific Publications Company name were available for a short
time, from about 1907 to 1914. Only a very limited range of models carried this name, one version of
the Mechanical Engineer, a Textile Calculator and the Type T Textile and Fowler’s Patent Pocket
calculator (later Fowler Type H) are the only ones known to date. However, by 1915 all pocket-watch
calculators carried the Fowler & Co. name.
ME Variants10
Introduction
The Mechanical Engineer, Mech Eng or ME has been consistently and regularly written about for
some considerable years. It is only after reviewing these articles that one realises that there are many
more variants than is obvious from a casual look at the type. This article attempts to produce a
definitive list.
The late Tom Wyman produced the first listing of the variants11 which followed the listing in
“Pocket Watch Slide Rules”12. It is neither complete nor definitive. Subsequent articles have looked
at the unusual ones, but not the actual variants which are not obvious unless one has something to
enable size comparisons, e.g. a coin. The “small” ME is a delightful fob-watch sized device and we
have identified six variants, there are three variants of “medium” and three variants of the “large”
device which is quite a weighty handful!
A simple visual presentation of the known variants under headings of “Small”, “Medium” and
“Large” follows. Please have a look at any examples in your collections and let me have any additions
and / or corrections where I might have made wrong assumptions. They at least deserve accurate
advertising on eBay.
The Variants
“Small”
Size
Weight
Case 2″ Φ; Scale 1¾″ Φ
75 gm
“Medium”
“Large”
Case 2⅜″ Φ; Scale 2″ Φ
94 gm
Case 3⅛″ Φ; Scale 2½″ Φ
215 gm
a)
No
Name
10
ME Variants, Peter M. Hopp CEng. MBCS Gazette 18, Autumn 2018, page 101
Pocket-Watch Calculators Produced by Scientific Publishing Company. Tom Wyman, Journal of the Oughtred Society, V. 22 No 1
Spring 2013.
12
Pocket Watch Slide Rules, Peter M. Hopp CEng. MBCS Astragal Press 2011. ISBN 978-1-931626-31-6
11
20
A Fowler’s Gallimaufry
“Small”
“Medium”
“Large”
b)
ME
scale
c)
Swiss
Label
No examples of “Swiss
No examples of “Swiss
Label”
‘medium’
are Label” ‘large’ are known.
known. Below is a detail
from a Small example.
d)
Swiss
Axle
From a ‘large’ calculator
This is a detail from a
n.b.
Price 6d weekly.
small
calculator.
No
examples
of
“Swiss”
‘medium’ are known.
e)
Sci
Pub
No
examples
of
“Scientific
Publication”
scale ‘small’ or ‘large’ are
known.
‘Sci Pub’ example with
engraved name on back.
Photo courtesy Peter Fox
21
A Fowler’s Gallimaufry
“Small”
f)
Green
Scale
“Medium”
“Large”
No examples of “green
No examples of “green
scale” scale ‘medium’ are scale” scale ‘large’ are
known.
known.
Photo courtesy David Riches
g)
No
Name
Type 2
These comments relate
No examples of ‘medium’
to the “small” calculator or ‘large’ No name Type 2
shown left, of which only calculators are known.
one example is known. No
examples of ‘medium’ or
‘large’
calculators
are
known.
The major difference
between this and Type (a) is
the different scale spacing
resulting in no space
between axle and first scale,
or is the ‘washer’ larger?
h)
John
Davis
Only a ‘small’ and a
‘large’ example with the
John Davis makers name on
the back are known.
Photos courtesy Peter Fox
22
A Fowler’s Gallimaufry
As well as these fourteen variants listed above, there are three further “unknown” relations to the
Mech. Eng. Genre. These are shown below.
Prototype ME?
Single Scale ME
Desk ME
13
Halden 1902 and Thornton 1916
catalogue
The Prototype ME has featured in a previous Gazette article14. I shall not repeat any of it here.
The Single Scale ME is a fairly recent discovery and is illustrated in “Pocket-watch Slide Rules”15
with no detailed comments. It is effectively just the outside scale of an ME in a “Small” case.
The Desk ME features in a 1902 Halden catalogue where it is advertised alongside a standard
“Mechanical Engineer” in Nickel Case at 7/6d, ditto – large size for desk at 12/6d. There is no
illustration; we can only assume it is a figment of someone’s imagination.
Figure 1.17: Cut from Halden 1902 catalogue
The Thornton 1916 catalogue shows an ME with only one winder (above). Again, either a
figment of someone’s imagination or else a plain and simple mistake – but to add confusion the
catalogue does mention a two dial calculator which the ME most definitely is not!
The actual illustration, complete with the numbers in an arc outside the case, has subsequently been identified as from the “FOWLER’S
CALCULATOR, FRONT DIAL” illustration in the “Instructions for Working Fowler’s Patent Pocket Calculator”, and also thus explains
the lack of side-winder as this would originally have had a back button. It does not really explain the “two dials” statement other than the
standard cubes and cube roots rear dial.
14
“A Quartet of Unusual Mech. Eng. Pocket-watch Slide Rules”. Peter M. Hopp. Gazette Issue 15, Autumn 2014. pp 139
15
Pocket Watch Slide Rules Ibid
13
23
A Fowler’s Gallimaufry
Fowler’s Pocket Watch Calculators
Introduction
Any description of the Fowler’s product range must follow on seamlessly from the description of
the Scientific Publishing range, it being self-evident that the same products (in some cases) were now
sold as Fowler’s calculators. An early attempt at a full classification of Fowler’s calculators 16 has
been subsequently updated 17 and now, starting from 1915, we can examine the prolific range of
pocket-watch calculators that are known to have been sold.
The earliest designs use the cast sintered Aluminum alloy case, and of course there are also
Fowler’s versions of the Scientific Publishing cast case ‘Calculator’ with the Centre button.
Fowler’s patents
Neither William Henry nor Harold Fowler were prolific patentees; however their five patents all
reflect solutions to problems that would have had to been overcome during the manufacture of these
devices.
Fowler’s Pocket-Watch slide rule Patents
Date
Patent No.
Patentee information
1910
UK 5,528
1913
UK 20,416
1914
UK 3,638
William Henry Fowler of 53 New Bailey Street,
Manchester, Engineer.
William Henry Fowler of Sale Lodge, Sale, Cheshire,
Engineer, and Harold Fowler, of ‘Alston’ Old Hall Road,
Sale, Cheshire, Engineer.
William Henry Fowler of ‘Oakleigh’ The Avenue, Ashtonon-Mersey, Cheshire, Engineer, and Harold Fowler, of
‘Alston’ Old Hall Road, Sale, Cheshire, Engineer
1914
UK 15,990
William Henry Fowler of ‘Oakleigh’ The Avenue, Ashtonon-Mersey, Cheshire, Engineer, and Harold Fowler, of
‘Alston’ Old Hall Road, Sale, Cheshire, Engineer.
1924
UK 215,648
William Henry Fowler of Station Works, Sale, Cheshire
(British) and Harold Fowler, of Station Works, Sale,
Cheshire (British).
William Henry Fowler’s first patent, No. 5,528, applied for on 5th March 1910, and accepted very
quickly thereafter on 23rd June 1910, is supposedly to simplify the construction of calculating
instruments and to avoid ‘derangement or fouling of the gearing or pointers’.
16
17
‘Fowler's Pocket Watch Type Calculators’; Peter Hopp in Journal of The Oughtred Society, Vol. 7 No 2, Fall 1998, pp 43 - 49
‘The Fowler Calculators – A Catalogue Raisonné’; Rick Blankenhorn & Bob de Cesaris in Journal of The Oughtred Society, Vol. 11 No
2, Fall 2002, pp 3 - 12
24
A Fowler’s Gallimaufry
This is very obviously the patent for Fowler’s
Patent Pocket Calculator and the unique calculators
with the single crown and a milled knob at the back
of the calculator that was used on at least two
designs of calculator illustrated in the earlier
Scientific Publishing section, and the Fowler E1 in
this section.
Patent No. 20,416 from William Henry Fowler
and Harold Fowler was the first joint patent from
father and son, both living in Sale, Manchester. The
patent was applied for on 7th September 1912 and
was awarded on 27th February 1913.
The patent covers a method of reducing the
expense of the design and improvements to enable
the radial shafts (which replaced the milled knob) to
be better fitted and more reliably ‘rendering the
boss immovable, and at the same time secure
Figure 2.1.1: Fowlers Patent 5,528/ 1910
extreme accuracy in the readings of the
instrument’. It is not easy to understand why they
took out this patent; the Mechanical Engineer calculators would have used such a construction 15
years previously.
Patent No 3,638 applied for on 12th Feb 1914, and
awarded 21st May 1914 is also in the joint names of Fowler
father and son still living in Sale, and is the first of two
patents awarded in 1914 for improvements to the design of
the calculators.
The drawing on the next page shows 4 of the 5 antibacklash designs that were suggested and obviously
implemented as can be seen in the illustrations of the
internals of the Fowler calculators in this and the last
sections.
Albeit that they did succeed in avoiding the ‘inexact
movements’ that are mentioned in the object, there is
nothing truly novel in the design and therefore rather
difficult to understand why the patent was issued.
Patent No 15,990 applied for on 4th July and awarded 3rd
December 1914, also in their joint names is the second
patent of 1914 and applies to ‘improvements in the method
of operating circular calculators or watch forms of slide
rule.’
Figure 2.1.2: Fowler patent 20,416/1913
It is again difficult to understand the reasoning for the
patent application, no types of slide rule to this design have
been seen, and it appears as if the Fowlers were trying to
revert to a type similar to that shown in their original patent
with the milled knob at the back, though this design uses a
form of ring to rotate the pointer.
25
A Fowler’s Gallimaufry
The final patent in the joint names of Fowler senior and junior is No 215,648, applied for on
September 6th 1923 under provisional patent No 22,418/23 and complete accepted on 15th May 1924.
They have reverted back to radial
shafts and this patent is intended to
improve the independent operation of
pointers and dials on the two sides of the
instrument, and the design allows a
definite and controllable amount of
frictional resistance to the circular
movement of the wheels rotating on a
common axis.
Once again it is possible to recognize
later designs of Fowler’s calculator in
this patent, those where the loop was
attached to a separate point on the rim
and two entirely independent knobs
working on radial shafts. This was
obviously the patent for the range of
variants with a central loop and two sidewinder designs, and gives us a date for
the introduction of that style of case.
Figure 2.1.3: Fowler patent 3,638/1914
It is always interesting to be able to follow the application of such a patent in the designs that
followed afterwards. This is definitely so here.
Fowler
design
evolution is difficult
to establish. The
earliest designs used a
cast
sintered
aluminum alloy case
which is actually very
brittle and must have
been
extremely
difficult
to
disassemble in the
event of requiring
repair. However we
know that this did
happen as we have
dated examples which
have been repaired.
A Fowler’s logo
which was used for a
short time, (c1948?)
is an intertwined
Figure 2.1.4: Fowler patent 15,990/1914
‘FC’, one assumes
standing for ‘Fowler’s Calculators’.
26
Figure 2.1.5: Fowler patent 215,6