D. CHEMISTRY AND METALLURGY. 187 



far as it can affect the rays F and G, is between seventy and 

 seventy-five miles high. The rays of whose chemical force 

 Marchand's actinometer gives an indication liave but one 

 seventh the force of the heat rays that accompany them, and 

 are 16,127 times less active than the chemical rays measured 

 by Bunsen and Roscoe. Marchand computes that the chem- 

 ical force received from the sun by the earth, each minute, 

 suffices to transform into carbonic acid nearly forty millions 

 of tons of carbon, and that the continuance of this chemical 

 action for a whole year would consume a stratum of coal cov- 

 ering the entire surface of our globe to the depth of about 

 one Inch. 6 B, 1873,760. 



SEPARATIOX OF DIGESTIVE FERMENTS. 



The interesting discovery has been made by Paschutin 

 that the ferments present in the intestinal juice of dogs, ^vhich 

 act on cane-sugar and starch, as well as the three ferments in 

 the pancreatic juice, can be separated by filtration through 

 porous porcelain cells. The filtration is difficult with an 

 aqueous extract of the pancreatic juice, but succeeds much 

 better with extracts made with concentrated solutions of 

 salts; and it further appears that solutions of different salts 

 extract the ferments in difterent proportions ; some, in fact, 

 taking one ferment, and that more completely than water. 

 Thus, the ferment which acts on albumen is extracted al- 

 most pure by Rochelle salt, hyposulphite of soda, nitrate of 

 ammonia, etc. ; that acting on starch, by arseniate of potash, 

 etc. ; that acting on fat, by antimoniate of potash, bicarbon- 

 ate of soda, etc. ; and Paschutin concludes that the nse of 

 concentrated solutions of salts will likewise facilitate the sep- 

 aration of the ferments of the intestinal juice. 18 C, A2Jril 9, 

 1873,237. 



LIQUEFACTION OF GASES. 



Melsens has lately made some interesting experiments on 

 the liquefaction of certain gases. It is well known that 

 charcoal can absorb its own weight of chlorine. Charcoal 

 thus saturated is placed in a siphon-shaped tube, hermetically 

 sealed. The long arm of the tube, containing the charcoal, 

 is then dipped in boiling water, while the short arm is im- 

 mersed in a freezins; mixture. The heat sets free some chlo- 



