302 



Scientific IntMigence, 



[ApRit, 



6» The nitrite possesses the following properties : It is little 

 soluble in cold water ; but boiling water dissolves nearly one- 

 tenth of its weight of it. It was decomposed by all the acids 

 tried. Even carbonic acid partially decomposes it, converting it 

 into subnitrite. Its constituents are. 



Acid 18-15 100 



Yellow oxide ... .81 '85 450 



7- The subnitrite possesses the following properties. The 

 colour is reddish yellow. It crystallizes in needles : 100 parts of 

 boiling water dissolve about three parts of it, and retain about 

 one part when cooled down to 73^. It is composed of 



Acid 9-9 .100 



Yellow oxide 90*1 9i0 



So that it contains double the quantity of oxide that exists in the 

 nitrite. See Ann. du Museum d'Histoire Naturelle, N® III. 

 p. 1888.. 



There is one circumstance in the above statement obviously 

 inaccurate. Chevreul says, that by the action of the lead the 

 nitric acid was resolved into nitrous acid and nitrous gas. Such 

 a resolution is impossible; because nitric acid contains more 

 oxygen than exists in nitrous acid and nitrous gas. The meaning 

 however, may be made out, though it is obscurely expressed. 

 What Chevreul must mean is obviously this: the nitric acid gave 

 out a portion of its oxygen to the lead, and the remainder was 

 resolved into nitrous acid and nitrous gas —an effect which might 

 very well happen. 



11. New Properties of Light, 



In our last number we gave a short summary of the new 

 experiments on light made by Dr. Brewster, and likewise of 

 what had been done on the same subject by Biot and Arrago in 

 France; but we have reason to believe that a more particular 

 explanation of some of the points will be acceptable to our 

 readers. 



The doable refraction of light by certain bodies has occupied 

 the attention of philosophers from the first observation of the 

 phenomenon by Bartholine and Huygens, down to our own 

 time ; but no satisfactory explanation of it has been offered. 

 Even Newton contributed l)ut little to the elucidation of this 

 difficult subject. Nor is the late effort of Laplace such as cor- 

 responds with his v/ell-earned celebrity, and with his eminence 

 as a mathematician. The phenomena of double refraction are 

 as follows : — 



If a ray of light fall upon one of tke surfaces of a rhomboid 



