CHEMISTRY. 149 



on the hand and allowed to remain there a few seconds. 

 On removing the wine, a mark is left which cannot be washed 

 out with water. 



Jacquemin has examined the methods proposed for the 

 detection of fuchsin in wine, founded on its tinctorial power. 

 As is well known, this substance is extensively used for this 

 purpose. Pyroxylin and wool may be dyed directly in the 

 wine, but to prove the presence of fuchsin finally, the ammo- 

 nia process is necessary. 



Maumene has published an extended memoir on an im- 

 proved method of alcoholometry for determining the strength 

 of wines, by distilling them first after making them alkaline, 

 and then the distillate after making it acid. The memoir 

 discusses at length the effects of the various foreign matters 

 present in wine upon the result, and concludes that the im- 

 proved method leaves nothing to be desired. 



Erismann has investigated very thoroughly the question 

 of the contamination of the air arising from artificial illumi- 

 nation and the distribution of the carbon dioxide in close 

 rooms. He finds that the injurious effect cannot always be 

 calculated from the absolute amount of carbon dioxide pres- 

 ent, since the quantity of the illuminating substance which 

 always escapes unburned is variable with the temperature 

 and the illuminant used. Moreover, the contamination bears 

 no necessary relation to the amount of light obtained. The 

 conclusions reached are: 1st, in every case of artificial illu- 

 mination the air of a close room contains more carbon diox- 

 ide and organic matter than when no light is present; 2d, 

 the proportion of marsh gas to carbon dioxide varies, not 

 only with the nature of the burning material, but also in 

 different strata of the air of the room when the same ma- 

 terial is employed, the ratio being never constant ; 3d, air 

 should never contain more than 0.6 or, at most, 0.7 per 

 thousand of carbon dioxide, otherwise products of imperfect 

 combustion are present in large quantity ; though, on the 

 other hand, a small quantity of this gas is no evidence of 

 freedom from these ; 4th, the position of the air-stratum in 

 which most products of combustion are found depends on 

 the nature of the burning: material, the hio-her strata being 

 most impure when candles are employed, though the larger 

 part of the carbon dioxide from combustion is removed by 



