146 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



A series of experiments has been made by Yogel on the 

 spectroscopic detection of carbonous oxide by means of a 

 solution of blood. While the spectrum of pure blood is 

 characterized by two bands in the green and yellow, which 

 bands disappear and give a single broader band by the ac- 

 tion of ammonium sulphide, blood which has absorbed car- 

 bonous oxide gas shows two similar but slightly more re- 

 frangible bands, not changing by ammonium sulphide. From 

 his experiments, the author infers that he can detect 0.8 of 

 one per cent, by volume of carbonous oxide in atmospheric 

 air in this way with perfect certainty. 



Cazeneuve has prepared pure hematin by treating defibrin- 

 ated blood by commercial ether for twenty-four hours, then 

 with more ether containing two per cent, of oxalic acid. This 

 ether being saturated exactly with ether containing ammo- 

 nia, deposits the hematin in flocks, which is purified by wash- 

 ing in water, alcohol, and ether. It combines with the ha- 

 loid acids to form crystallized salts, and has the formula 

 C 68 H 70 N e Fe 2 O 10 . Concentrated hydrochloric acid splits it 

 into two red bodies, one containing 37.62 per cent, of iron, 

 the other 2.08 per cent. 



TECHNICAL. 



Berthelot has investigated more extensively the occurrence 

 of benzene in coal-gas. Its presence there is due to the high 

 temperature of the carbonization as well as to the prolonged 

 heat, during which an equilibrium is established between the 

 various hydrocarbons. If the distillation be effected at a 

 low red heat, the gas may differ in its composition. The au- 

 thor's experiments were directed to ascertain experimentally 

 the reliability of the method used by him in his analysis, i. e., 

 absorbing the benzene vapor by fuming nitric acid. The re- 

 sults of direct tests and also of endiometric comparisons 

 were favorable, and established his assertion that in Paris 

 gas benzene is the principal illuminant. 



Ilumpidge, under Frankland's direction, has analyzed and 

 tested the gas of London. lie finds (1) that the gas now is 

 no better than that analyzed by Frankland twenty-five years 

 ago, and (2) that the apparent increase in its illuminating 

 power is due solely to improvements in the test burner. 



Mendelejeff has proposed a new hypothesis of the origin 



