566 Intelligence and Miscellaneous Articles. 



to distinguish it from the crude article of commerce, M. Robiquet 

 gave it the name of aloetine. 



The properties of aloetine are that, when prepared out of the con- 

 tact of the air as much as possible, it is in the form of nearly colour- 

 less scales, which are very soluble in water and alcohol, slightly 

 dissolved by aether, and perfectly insoluble in fixed and volatile oils ; 

 when calcined in close vessels it leaves merely a bulky and brilliant 

 charcoal, which disappears entirely by calcination. Aloetine is not 

 coloured by the salts either of protoxide or peroxide of iron, and 

 gives no precipitate with acetate of lead ; in other respects it acts 

 upon reagents similarly to Socotrine aloes. 



If aloetine be dried in contact with the air, the scales obtained, 

 instead of being nearly colourless, have an intense red colour derived 

 from a slight absorption of oxygen. Except this difference of colour, 

 aloetine altered by the air undergoes no change of chemical proper- 

 ties, and analysis scarcely shows any difference between them. The 

 purification of aloes may be much shortened by drying it by the 

 water-bath or exposure to the sun, when it is not required to be of 

 the utmost purity. 



M. Robiquet gives the following as the results of his analysis of 

 aloetine, and also a formula, which, however, he states as an approxi- 

 mation only : — 



Weight of the 

 Theory. equivalent. 



Carbon 27'69 450 C 6 



Hydrogen 1077 175 H 14 



Oxygen 61-54 1000 O 10 



100- 1625 C 6 H I4 10 



M. Robiquet states that aloetine possesses in the highest degree 

 the purgative property and bitter taste of common aloes : medici- 

 nally employed, 8 parts of aloetine represent 10 parts of Socotrine 

 and 50 parts of Cape aloes. — Journ. de Pharm. et de Ch., Septembre 

 1846. 



WOHLER S PROCESS FOR THE PREPARATION OF PURE HYDRO- 

 CYANIC ACID. 



Cyanide of potassium is prepared by fusing together 8 parts of 

 dry ferrocyanide of potassium and 3 parts of pure carbonate of pot- 

 ash containing carbon (ignited cream of tartar), and 1 part of char- 

 coal in fine powder in a covered crucible; the mass while still 

 warm is powdered, and placed in a stoppered bottle of such a capa- 

 city that when 6 parts of water are added the bottle is quite filled *. 

 When the cyanide of potassium is dissolved and the metallic iron is 

 all deposited, the clear solution is poured into the retort a. The 



* The cyanide prepared by Liebig's process is less fit for the preparation of 

 prussic acid ; on account of the large amount of cyanate of potash it contains, 

 much carbonic acid is disengaged, which renders the condensation of the acid far 

 more difficult. 



