566 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
THE FIRE PISTON IN EUROPE. 
Appreciation by physicists of the scientific fact that heat and cold 
may be produced by the mechanical condensation and rarefaction of 
gases dates back to before the commencement of last century. A 
paper upon this subject was read by John Dalton in the year 1800, ¢ 
giving the results of experiments in the compression and rarefaction 
of air, which were noted as producing increased and decreased tem- 
peratures. On December 29, 1802, M. Mollet, professor of physics in 
the Central School at Lyons, announced to the Institute of France 
that he had noticed that tinder could be ignited by placing a small 
piece in the narrow channel with which the lower end of a pump for 
condensing the air in an ordinary condensation pump is furnished. 
Two or three strokes of the piston were usually sufficient to cause a 
spark.” He also stated that he had observed a luminous appearance 
caused by the discharge from an air gun in the dark. On the 
strength of this announcement, J. C. Poggendorff ¢ refers to Mollet 
as the discoverer of the Tachypyrion (instrument for producing fire 
by compression of air). On the other hand, we may gather from F. 
Rosenberger @ that a workman in the small-arms factory at Etienne- 
en-Forez (near Lyons) was the actual discoverer of the fact that a 
great amount of heat was generated in charging an air gun with an 
ordinary compression pump, and that tinder could be ignited thereby. 
Mollet is here stated to have communicated this discovery by the 
workman, who must, if Rosenberger’s account is the true one, be 
credited as being the original French observer of this phenomenon, 
Mollet having acted as the reporter of the discovery. The facts an- 
nounced were not understood by the French scientists, who were in- 
clined to discredit them, but very soon the experiment with the air- 
compression pump was repeated by others, and tinder (amadou) was 
easily ignited by this means. <A letter was sent by M. A. Pictet, one 
of the editors of the Bibhothéque Britannique, to Mr. Tilloch in Eng- 
land, on January 1, 1803, announcing Mollet’s communication to the 
Institute of France,’ and the writer stated that he considered the 
phenomenon as never having been noticed before. But William 
Nicholson affirmed’ that it (the flash from an air gun) had been 
“Mem. Manchester Lit. and Phil. Soe., V. pt. 11, p. 515, 1802. 
+ Journal de Physique, LVIII, 1804, p. 457; Nicholson’s Journal of Nat. Phi- 
losophy, Chemistry, and the Arts, IV, 1808; Philosophical Magazine, XIV, p. 363. 
¢ Biograph.-Literarisches Handworterbuch, II, 1863, Leipzig. 
¢ Geschichte d. Physik, 1887, III, p. 224. 
€ Philosophical Magazine, XIV, p. 363. 
f Nicholson’s Journal, 1. ¢.; Mare Auguste Pictet, ‘Sur l’échauffement des 
projectiles par leur frottement contre lair,’ Bibliothéque Britannique, XXIII, 
1803, pp, 331-3386, 
