232 Intelligence and Miscellaneous Articles, 



not obtain the compound of sulphuric and chromic acids described 

 by M. Gay-Lussac in the 16th volume of the Ann. de Chim. et de 

 Phijs., and he is inclined to question its existence. — L'Institut, 

 No. 341. 



COMPOSITION OF CRYSTALLIZED PHOSPHORIC ACID. 



In the opinion of Prof. Graham, phosphoric acid may combine 

 with water in three different proportions, and form a phosphate, 

 biphosphate, triphosphate of water. The existence of these com- 

 pounds has hitherto been hypothetical, except the first, which ap- 

 pears to be vitrified phosphoric acid. The analysis of crystallized 

 phosphoric acid has not yet been attempted, or at any rate not yet 

 published. M. Peligot has attempted to supply this void in the 

 history of phosphoric acid, by analysing crystals which slowly formed 

 spontaneously in bottles filled with syrupy phosphoric acid. One 

 of these bottles contained two very distinct crystalline layers. The 

 upper crystals were transparent and hard ; the lower ones were soft, 

 and had the appearance of sugar of honey. 



The crystals, separately collected, were dried in vacuo, on plates of 

 absorbent porcelain ; the quantity of water was determined by cal- 

 cining them with oxide of lead. According to M. Peligot's analyses, 

 the upper crystals contained from 27 to 28 per cent, of water, and 

 the lower crystals 22 to 23 per cent. 



The extreme avidity of these crystals for water, renders a precise 

 analysis of them very difficult ; if, as theoretically supposed by 

 M. Peligot, hydrated phosphoric acid containing three equivalents 

 of water ought to contain 27 '4 per cent., and the bihydrate 20*1 per 

 cent., it will appear probable that the crystals examined were in fact 

 these two hydrates. Their properties also corroborated this opinion ; 

 for the most hydrated acid, when saturated with ammonia, precipi- 

 tated silver of a yellow colour, while the second precipitated it white. 

 — Journal de Fharm., Juin, 1840. 



DETECTION OF ALCOHOL IN ESSENTIAL OILS. 



For the above" purpose M. Borsarelli employs a small cylindrical 

 tube closed at one end ; this is two-thirds filled with the oil, and there 

 are dropped into it small pieces of chloride of calcium, which are 

 quite dry, and free from powder; the tube is then closed, and heated 

 in a water-bath to 212° for four or five minutes, taking care to agi- 

 tate it occasionally, and to allow it to cool slowly. 



If the essential oil contains a notable proportion of alcohol, the 

 chloride dissolves entirely, and forms a liquid stratum, which occu- 

 pies the lower part of the tube, while the essential collects in the 

 upper. If the oil contains only a very small portion of alcohol, the 

 fragments of chloride of calcium effloresce, lose their form, and 

 unite at the bottom of the tube into a white adhesive mass ; when 

 it is quite pure the pieces of chloride suffer no change, even in their 

 form. 



