238 Intelligence and Miscellaneous Articles. 



^ OSiti T! Deflection, 



the analyzer. 



55 . 



55 0-1 



— 35 20-5 



+ 10 10 



+ 100 10-5 



For positions of the analyzer equally distant from 55 the deflec- 

 tions are equal ; and the sum of those obtained at + 10 and +100 is 

 equal to that obtained at — 35, as it ought to be. The division of 

 the scale employed in these measurements goes up to 180 on each 

 side of zero. The quartz was always the same. 



I shall finish this note by adducing some observations of a totally 

 different nature, which appear to confirm my previous results. M. 

 Dumoulin-Froment had the goodness to lend me a grating which he 

 himself had constructed. On this delicate apparatus I let fall a 

 solar pencil, transmitted through a narrow aperture, and concen- 

 trated by a lens ; at a suitable distance I obtained, on a screen and 

 with great distinctness, the phenomena of Fraunhofer. By placing 

 the pile in the dark spaces which extend from one side to the other 

 of the central pencil, I obtained no deflection. The needle, on the 

 contrary, was sometimes deflected as far as 15 degrees by the action 

 of the green, yellow, or red rays of the first spectrum. The limit 

 of the extreme red of this spectrum touched the violet of the second. 

 Receiving in addition the rays within this region, I obtained 10 de- 

 grees more of deviation ; at a greater distance the effects rapidly de- 

 creased, and in the conditions of my experiments I only obtained a 

 deflection of 2 to 3 when I received on the pile the orange and the 

 yellow of the second spectrum, with the portions of red and of green 

 the nearest these colours ; but (and this is the point on which I 

 dwell) by interposing in the path of the rays the trough full of io- 

 dized sulphuret, I extinguished all the effects produced by heat 

 which are found in the visible part of the first spectrum, and as far 

 as the violet of the second ; while, when the pile was so placed as to 

 receive the green, the yellow, and the orange of the second spectrum, 

 the interposition of the sulphuret did not completely extinguish the 

 calorific action. Such was then, in the first spectrum, the position 

 of the obscure rays transmitted through the sulphuret. These latter 

 results were obtained with a very delicate pile, constructed by M. 

 Ruhmkorff according to the recent directions of M. Edm. Becquerel. 

 — Comptes Rendus, June 11, 1866. 



ON THE USE OF NITROGLYCERINE IN THE QUARRIES OF VOS- 

 GES1AN SANDSTONE NEAR SAVERNE. BY M. E. KOPP. 



The fulminating properties of nitroglycerine, C 6 H 5 (NO 4 ) 3 O 6 , and 

 the experiments made with this substance in various localities of 

 Sweden, Germany, and Switzerland, have led MM. Schmitt and 

 Dietsch, proprietors of the great quarries of sandstone in the valley 

 of the Zorn (Lower Rhine), to try its use also in their workings. 



The success has been so great, both as regards economy and faci- 



