262 SCIENTIFIC NEWS. 



to make exertions proportioned to the difficuliy of the 

 subject. The prize which will be proclaimed in the pub. 

 lie sitting of the first Monday in January 1809 will be a 

 gold medal of 6000 francs ci^SO). 



The works presented must be written either in French 

 or in Latin, and will not be received later than October 

 1, 1808. This term will l>c strictly attended to. The 

 other conditions are as usual. 



Nitrate of Soda. 

 Nitrate of soda Professor Proust writes to Dr. D 'lamether.?, that he 



."["^ ^ ^^f finds the nitrate of soda an economical article for fire 

 times as long 



as common ni- works. Five parts of the nitrate, one of charcoal and 



trc,&c. one of sulphur, afford a powder which gives a flame of 



a reddish yellow, of considerable beauty : and the mixture 



burned in a metallic tube, will last exactly three times as 



long as the same charge of common powder. 



The nitric acid in this combination is not decomposed 

 to the same degree as that of nitrate of potash. Its 

 ga^es are a mixture of carbonic acid, with a small quan- 

 tity of gaseous oxide of azote, and much nitrous gas. 

 The cheapest method of obtaining nitrate of soda, 

 > would no doubt be to use soda, instead of potash, to satu- 

 rate the mother waters. 



'l Examination of the Birds'' Nests which are eaten in 



Chiiia^ and other Eastern parts, 



JSii'ds^ nests of The same chemist has examined the birds' nests of the 



the East. j^^g^ ^j^(j gjjjjg ii^Qjy^ to consist merely of a single piece of 



' cartilage, uniform in its texture. IJe boiled one in 



water, which became soft, but was not separated in its 



parts and what was still more remarkable, it lost only 



four hundredths of its wt^ight. 



Subterraneous Road or Tunnel, made upwards of three 

 ^ Centuries ago (Jour?ial des Mines ^ Fcv. 1806). 

 Subterraneous The Marquis (de Saluces) Louis II. being desirous of 

 passage or tun- increasing the commerce of the country dependant on 

 madc"in''die his sovereignty, undertook in the fifteenth century to 

 fifteenth cen- pake an excellent road in thciuHey of the Po, which 

 tury. ' passing 



