476 A. G. Bell— Production of Sound by Radiant Energy. 
Since the publication of the memoirs of Réntgen* and Tyn- 
dallt we have repeated these experiments, and have extended 
the inquiry to a number of other gaseous bodies, obtaining in 
every case similar results to those noted in the memoirs re- 
ferred to. 
The vapors of the following substances were found to be 
highly sonorous in the intermittent beam: water vapor, coal 
gas, sulphuric ether, alcohol, ammonia, amylene, ethyl bromide, 
diethylamene, mercury, iodine, and peroxide of nitrogen. The 
loudest sounds were obtained from iodine and peroxide of 
nitrogen, 
I have now shown that sounds are produced by the direct 
action of intermittent sunlight from substances in every physi- 
cal condition (solid, liquid, and gaseous), and the probability 
is therefore very greatly increased that sonorousness under such 
circumstances will be found to be a universal property of 
matter. 
Upon Substitutes for Selenium in Electrical Receivers. 
_ At the time of my communication to the American Associa- 
tion the loudest effects obtained were produced by the use of 
soon, I shall make no further mention of his investigation than to 
state that he has found sulphur, iron, lead, and arsenic in the 
so-called “selenium,” with traces of organic matter; that a 
quantitative examination has revealed the fact that sulphur 
constitutes nearly one per cent of the whole mass; and that 
when these impurities are eliminated the selenium appears to 
be more constant in its action and more sensitive to light. 
Professor W. G. Adamst{ has shown that tellurium, like 
* Ann. der Phys, und Chem., 1881, No. 1, p. 155. 
i, p. 307. 
+ Proc. Roy. Soe., vol. xxxi, p. 
t Proc. Roy. Soc., vol. xxiv, p. 163. 
