78 Scientific Intelligence. [Jan. 



oil from the liquid by alcohol. M. Payen has shewn that the seat 

 of this oil is in the tegumentary part of the fecula of potatoes. Those 

 who have examined the oil proceeding from the spirit of barley, de- 

 scribe it as capable of crystallization, volatilizing with difficulty, un- 

 dergoing alterations by distillation, and staining paper permanently. 

 Pelletan found on the contrary, the oil from the spirit of potatoes to 

 be a true essential oil. Dumas examined a specimen from the manu- 

 factory of Dubrunfaut; it possessed a reddish yellow colour, and a very 

 disagreeable smell. When one breathes the air charged with it, 

 nausea and head-ache are produced. Carbonate of potash diminishes 

 the odour considerably, and when distilled with it renders it analogous 

 to that of nitric ether. In order to free it entirely from alcohol, it is 

 necessary to distil cautiously, and obtain a residue of pure oil boiling at 

 130° (266° F.) or 132° (269°) the alcohol passing over first. Dumas 

 suggests that although bearing some affinity to alcohol and ether, it 

 may belong to the family of camphors. The density of its vapour is 

 3*147, or calculating from the composition 3*072. It consists of: — 



Carbon .... 68*6 



Hydrogen ... 13*6 



Oxygen .... 17*8 



IV. — Mode"of Detecting some Organic Acids. By H. Rose, 

 (Poggendorff's Annalen. xxxi.) 



Tartaric, racemic, citric, and malic acids may be readily detected in 

 the following manner : dissolve them in as small a quantity of water 

 as possible, and add to the solution an excess of lime water, so that 

 reddened litmus paper may become blue. 



Tartaric and racemic acids form a precipitate in the cold state. 

 That produced by the tartaric acid dissolves completely in a small 

 quantity of a solution of ammonia, while that of the racemic acid re- 

 mains insoluble. Both acids can likewise be readily distinguished 

 by their treatment with a solution of sulphate of lime, when after 

 some time racemate of lime is deposited, while the solution of tartaric 

 acid is not affected. 



The solution of citric acid yields no precipitate with lime water in 

 the cold state, but when heated, a considerable precipitation occurs. 

 If a small quantity of a very dilute solution of citric acid is mixed 

 with lime water, a precipitate falls by boiling, which is taken up by 

 allowing the solution to cool. The solution of malic acid occasions 

 no precipitate with lime water, either in the cold or by boiling. For 

 these experiments completely saturated lime water, should be em- 

 ployed. 



V. — Iron Mine of Rancie. By M. Dufrenoy. 

 (Ann. des Sciences Naturelles, xxx. 59.) 



The formation of Vic Dessos, consisting of a compound of white 

 saccharoid limestone, black compact limestone, shistose limestone, 

 belongs to the inferior portion of the Jura formations. 



The Hematite of Rancie contained in this deposit, is disposed in 

 layers, and is connected with the granite at a little distance from 



