** **

**John
Perry and Alwin Walther, two pioneers of engineering mathematics.**

** **

** **

**Figure
1: Dr. John Perry**

**Figure
2: Thornton Perry Slide Rule**

**Figure
3: Nestler Perry Slide Rule**

**Figure
4: Nestler Peter Slide Rule**

**Figure
5: Dr. Alwin Walther**

**Figure
6: Faber-Castell 1/54 Darmstadt Slide Rule**

1. *"Höhere
Mathematik für Ingenieure"* von Dr John Perry, FRS, Dritte Auflage,
1919, B.G. Teubner, Leipzig-Berlin, Vorwort zur ersten Auflage (1902) p
viii. The original edition is *"The
Calculus for Engineers"* by John Perry, 1st edition 1896 by E. Arnold,
London.

2. Sir
William Thomson, later Lord Kelvin of Largs, (1824 - 1907), English Physicist,
one of the greatest natural scientists of the 19th century.

3. *"Elementary Practical Mathematics, with
numerous exercises for the use of Students",* Prof. J. Perry, Macmillan
& Co, London, 1913.

4.
*"Practical Mathematics, Summary of six
lectures, delivered to working men"* by Prof. John Perry at the Museum of Practical Geology, Jermin Street,
February and March, 1899, with certain exercises supposed to be worked after
every lecture. 1899.

5. *"Obituary Notices of Fellows
deceased" *By H.H.T. in the Proceedings of the Royal Society, 1,1926,
piii. "*It is, fortunately, not necessary to discuss whether Perry's direct
contribution to knowledge, or those which flowed from his own teaching and his
influence on other teachers, are the most important. *The obituary goes on to cite: *A report by The Mathematics Association
titled "Teaching of Mathematics to Evening Technical Students"* *opens in the following words:
"Mathematics has long been recognised as an important element in the
education of engineering and other technical students. Much thought has been devoted to the problem
of presenting mathematical ideas in such a form that they can be assimilated
and applied to technical problems. At
one time the presentation was undoubtedly too abstract. This tendency has now disappeared, chiefly
owing to the efforts of the late Prof. Perry.
His methods have been adopted very widely. When they were first introduced, they aroused
great enthusiasm, and it was hoped that henceforth no difficulty would be
experienced in imparting a good working knowledge of mathematics to every
student of average capacity. Subsequent experience has proved that these hopes
were too sanguine. Some very good work
has been done, both by teachers and students, and yet in the opinion of many,
the results obtained are somewhat disappointing".*

6. *"Höhere
Mathematik für Ingenieure"* see (1).
Preface to the 1st edition.

7. "Prof. Dr. Robert Fricke, o
Prof. der Mathematik an der Technischen Hochschule zu Braunschweig, und Fritz
Süchtig, o Prof. für Maschinenkunde und Elektrotechnik an der Bergakademie zu
Clausthal".

8. Florian
Cajori - *"A History of the
Logarithmic Slide Rule and Allied Instruments",* mentions in the
preface page iii *"advanced
mathematicians as Segner, Perry, Mannheim, Mehmke and the great Isaac
Newton".* He also lists the
"Perry Slide Rule" at 1902, and "Perry's New Slide Rule" at
1908, placed on the market by A.G. Thornton.

9.
Letter from
Günther Kugel to the author about Nestler's Perry and Peter slide rules.

10. *"Faber-Castell Rechenstäbe System
Darmstadt"* Dr.-Ing. E.h. Günther Kugel; Historische Bürowelt, 1997,
No. 47 pp 25-30; No. 48 pp 27-30.

11. For
example, the Unique Brighton slide rule, and the Sun-Hemmi No 130.