Intelligence and Miscellaneous Articles. 41 3 



When a mixture of peroxide of iron and potash is kept for some 

 time at a strong red heat, a brown mass is obtained, which, 

 treated with water, gives a solution of a very fine violet-red colour ; 

 this compound is very soluble in water, but a large quantity of water 

 eventually decomposes it : it becomes insoluble in water which is 

 very alkaline, but gives a brown precipitate, which dissolves readily 

 in pure water, and yields a solution of a fine purple colour. It ap- 

 pears to be much less permanent than manganate of potash ; under 

 certain circumstances it decomposes at common temperatures into 

 oxygen gas, which escapes, and peroxide of iron which precipitates ; 

 and a solution of free potash remains, which is perfectly colourless. 

 At 2 1 2° Fahr. it undergoes similar decomposition instantaneously : 

 all organic substances decompose it ; consequently it is impossible to 

 filter the solution. 



This compound may be more readily prepared, and in a few mi- 

 nutes, by calcining, at a high temperature, a mixture of nitre, potash 

 and peroxide of iron ; or by heating a mixture of peroxide of potas- 

 sium and peroxide of iron. This compound was also formed in the 

 humid way by passing a current of chlorine gas into a very concen- 

 trated solution of potash, holding peroxide of iron in suspension. 



The fact stated seems to indicate the existence of a body more 

 highly oxygenated then peroxide of iron. M. Fremy could not, 

 however, isolate any such compound ; for when the solution is 

 treated with an acid, and the potash is saturated, oxygen is disen- 

 gaged and peroxide of iron is precipitated ; if the acid is in excess, 

 the peroxide of iron is dissolved, and a salt of this oxide is formed. — 

 Journal de Pharmacie, torn, xxvii. p. 97. 



PREPARATION OF GUAIAIC ACID. BY M. THIERRY. 



To prepare this acid M. Thierry dissolves the pure guaiacum resin 

 of commerce in the requisite of alcohol, sp. gr. (56 c.) ; the tinc- 

 ture is to be filtered, and three-fourths of the spirit used are to be 

 distilled ; when the operation is over there remains in the retort a 

 yellowish liquor, above a quantity of resin ; when cool the liquor is 

 to be filtered. 



This liquor is acid, and is to be saturated with barytes water, with 

 which it forms" a soluble salt ; the liquor is to be evaporated to half 

 in a water-bath, and the guaiacate obtained is to be decomposed by 

 dilute sulphuric acid ; and it is better that a little of the salt should 

 remain undecomposed, rather than excess of acid should be used ; 

 for the latter during the concentration of the guaiaic acid reacts 

 upon and decomposes a portion of it ; if, however, any should have 

 been employed, a little barytes water may be used to precipitate it ; 

 when the sulphate of barytes has been separated the solution is to 

 be evciporated in a water-bath to the consistence of a syrup ; the 

 residue is to be put into a matrass, and the mixture is to be shaken 

 repeatedly for some time ; the aether dissolves the guaiaic acid, but 

 does not act upon the extractive matter ; the liquor is to be de- 

 canted, and when the aether is evaporated, the guaiaic acid is de- 

 posited in irregular mammillated masses on the sides of the vessel. 

 The acid thus obtained is not however quite pure ; it contains some 



