NATURAL PHILOSOPHY. 147 



the part of the spectrum near h. They vary in intensity, fine- 

 ness, and mode of o:rouping, and exhibit some slight free spaces. 

 They have no regular order, and extend beyond the ray F toward 

 the ray 2,110 of Kirchhoft"'s scale. In this last portion they are 

 very numerous and almost equidistant. The solar spectrum 

 proper continues visible as far as 2,210, but after that the light is 

 completely absorbed. Chlorine, therefore, absorbs the colored 

 portion of the sijectrum, where the chemical rays are most abun- 

 dant. 



SOME PHENOMENA OF DECOMPOSITION PRODUCED BY LIGHT. 



M. Morren, in the " Comptes Rendus,"of Aug. 9, 1869, in refer- 

 ring to TyndalFs late researches on the vapors of different bodies 

 submitted to light, says : — 



"If a body forms and maintains itself in certain undulatory 

 conditions, it is necessary that the oscillations of the atoms which 

 constitute its molecule should be different from those of the me- 

 dium where the bod}' has been produced. But if the body is trans- 

 ported into another medium, where vibrations synchronous with 

 those of its atoms are produced, the vibrations of these last be- 

 come more energetic, and the live force, which they accumulate, 

 thus becoming considerable, the atoms are thrown to a distance 

 from each other greater than the radius of their sphere of action. 

 The atomic edifice, previously formed, is demolished; the atoms 

 preserving their special attractions for a new edifice, possible 

 in the conditions of oscillation which surround them, consequently 

 not possessing longer the same synchronous oscillation as those 

 of the medium." 



We refer the reader to the "Comptes Rendus," of Aug. 9, 

 1869, for a more extended exposition by M. Morien ; he says, in 

 addition, that the acid-sulphate of quinine placed between two 

 plates of glass, and of a thickness of from 4 to 5 millimetres, af- 

 fords an admirable screen for cutting oft' chemical rays, and can 

 replace advantageously the yellow glass of the photographer. 



A NEW THERMO-ELECTRIC PILE. 



This apparatus is formed of GO elements ; these elements are 

 composed of little bars of galena, or sulphuret of lead (sulphiire 

 natural de plomb), and some plates of sheet iron; the bars are 40 

 millimetres in length, and 8 in tlrickness ; the plates of iron 55 

 millimetres in length to 8 in breadth, and 6mm. in thickness. 

 In these couples the galena is the electro-negative element, the 

 iron the electro-positive. The form of the bars is such, that in 

 placing them side by side they form a crown of 12 couples, the 

 interior of which is formed by the extremities, which are heated. 

 The couples are united in tension by a soldering of tin. They are 

 ii^olated from one another by some thin plates of mica. In su- 

 perposing upon each other 5 of these crowns, one forms a battery 



