390 • Selenium as a Reguh~tor of Heat. [Jour. Frank. Inst.,

N e w Analys is of Tobacco Smoke.---G. Le Bon, and G. Noel, have sent to the French Academy three vials, containing products which they have suceeeded in extracting from tobacco smoke. They are: 1, prussic acid; 2, an alkaloid of an agreeable odor, but dangerous to hreathe, and as poisonous as nicotine, slnce ~- of a drop destroys animal life; 3, aromatic principles, which are as yet unde- termined, but which contribute , with the alkaloid, to give the smoke its perfume. The alkaloid appears to be idefitical with collidine, which has been observed in the distillation of many organic sub- stances, but its physiological and poisonous properties have been hitherto unknown.--Comptes Rendus. C.

Relation be tween the Major and Minor modes in Nusic . - -F . Ricard has been experimenting with a key board of equal temperament, and finds that inversion changes the mode from major to minor, and vice versa. M. Corun, without adopting Ricard's views upon the constitution of musical scales, thinks that this curious in- version is worthy of study, and that it may throw some light upon the obscure questions relative to 4he interpretation of major and minor melodies.-- Comptes Rendus.

[The "Orginuette" furnishes great facilities for experimenting on inversion. Some of t h e results are very curious, and if they are carefully investigated, they may lead to important scientific con- clusions.] C.

Selenium as a Regulator of H e a t . - - P . Germain proposes to use the various degrees of resistance which selenium opposes to the passage of el~tricity at different temperatures and under different rays of the spectrum, to the regulation of the temperature, in muffles for enameling painted glass or porcelain. He uses a thermo-electric bat- tery of thirty element% which receives the heat directly from the nmf- fie. The opposite pole is connected with the wall of a porous vessel, full of water, which maintains a sensibly constant temperature. The thermo-electric current increases in potential proportionally to the ele- vation of the temperature in the muffle. The selenium is brought into the circuit, but it remains comparatively unaffected until the muffle has reached t h e proper luminous temperature, when it allows the current to pass dnd to give a" signal by means of a bell.--Comptes Rendus. C.