370 Notices of the Labours of Continental Chemists. 



It is decomposed by all organic substances, from which cause 

 it is impossible to filter the solution. Hitherto all attempts 

 to isolate the combination have proved unsuccessful. When 

 the red solution is treated with an acid and the potash nearly 

 saturated, peroxide of iron is thrown down and oxygen dis- 

 engaged. — Comptes Rendus, vol. xii. p. 23. 



Oti the series of Bodies derived from the fuming liquor of 

 Cadet (Alkarsi7i). 



In a paper entitled " Researches on the Cacodyl Series," 

 Aujialen der Chemie und Pharmacies xxxvii. p. 1, Dr. Bunsen 

 has described the products of the decomposition of alkarsin. 



The primary member of this series has the formula 

 C^ H'- As-, and therefore represents common alcohol, in 

 which two atoms of oxygen are replaced by two of ar- 

 senic. This body may be taken as an excellent repre- 

 sentative of the organic radicals. The arsenic in these com- 

 pounds cannot be completely oxidized by nitric acid ; more- 

 over, it cannot be determined by means of the usual oxidizing 

 substances, or of oxide of copper, because explosions fre- 

 quently occur, and the separation of arsenic from copper is 

 difficult. The best substance is oxide of nickel, which may 

 be prepared by heating the sulphate to a white heat; by 

 burning the compound with this oxide the arsenic is fully 

 oxidized, but not so the carbon and hydrogen. The tube for 

 burning is connected with a Liebig's condenser, containing 

 water; if the analysis has not been well conducted this water 

 acquires a smell of alkarsin. The contents of the tube are 

 quite soluble in aqua regia; the solution is treated with sul- 

 phuric acid to drive off the nitric acid, evaporated to dryness, 

 moistened and filtered : in this solution the arsenic may be 

 determined in the usual method. The carbon and hydrogen 

 may be determined by burning the compound with oxide of 

 copper or chromate of lead ; if oxide of copper be used, a 

 rather long tube must be employed, the anterior part of which 

 is filled with chromate of lead or copper turnings. In pre- 

 paring these compounds all the vessels must be filled with 

 carbonic acid. 



Oxide of cacodyl, alkarsin (vide yhmalen xxiv. ; also Du- 

 mas, Annalen, xxvii.). Formula O H'- As', O. Specific gra- 

 vity of the vapour, found by experiment, 7"555, calciilated,7*832. 



This body reacts perfectly neutral, but combines with acids, 

 and in this respect is similar to some inorganic bodies, which 

 are half base half acid. Phosphoric acid dissolves a large 

 quantity of it, and forms a stinking thick fluid which does not 

 crystallize. The alkarsin may be distilled over from this 



