464 A. G. Bell—Production of Sound by Radiant Energy. 
The substance to be tested was to be placed in the interior 
of a transparent vessel, made of some material fol tase glass) 
is transparent to light, but practically opaque to s 
Under such circumstances the light could oo ic but the 
sound produced by the vibration of the substance could not get 
out. The audible effects could be studied by placing the ear 
in communication with the interior of the vessel by means of a 
m 
Bn by M. Me reo Prof. Tondllt W. - “Tontaen 
d W. i. Preece,| I may be permitted to quot 
Teer to Mr. Tainter the passage describing the exiistbis 
referred to 
“* Metropolitan Hotel, Rue Cambon, Paris, 
November 2, 1880. 
ey uae Mr. "TAINTER : 
“T have devised a method of producing sounds 
me action of an intermittent beam of light from substances that 
cannot be obtained in the shape of thin Rachtians or in the tu 
ular form; indeed, the method is specially adapted to testing the 
generality of the phe nomenon we ee discovered, as it can be 
adapted to solids, liquids, and gase 
“Place the substance to be eepedaeaied with in a glass test- 
tube, connect a rubber tube with the mouth of the test-tube, plac- 
large number of substances in this with great success, 
although it is extreniely difficult to get a a plingpee of the sun here, 
and when it does shine the intensity of the ae is not sg be com- 
pared with that to be obtained in Washington. I got splendid 
effects from crystals of picheomate of potash, onset of qalphate 
* Comptes Rendus, vol. xcl, p. 5 
+ “ Notes on Radiophony,” * ahenser Rendus, Dee. . and 13, 1880; Feb. 21 and 
28, 1881. See, also, Saal de -baedegr vol. x, p. 5 
+ « Action of an Intermittent m 0 iant Heat upon Gaseous Matter.” 
Proc. Royal Society, Jan. 13, 1881, ak XXxi, PA 
2 On the tones which arise from the intermittent cose of agas.” See 
Annalen der Phys. und Chemie, Jan., 1881, no. 
“On the Conversion of Radia nt ae into Ronorous Vibrations.” Proc. 
Royal Society, March 10, 1881, vol. xxxi, p. 5 
