ALKALIMETRIC TEST FOR IRON. 41 



deposit (often abundant) formed on tlie boilers and in the flues 

 from the combustion of the waste-gases. A deposit of this 

 kind, from the Conshohocken furnace of Mr. Colwell, was 

 analyzed in the laboratory of one of us, by Mr. W. Fisher 

 and Mr. J. Colwell, and proved to be almost wholly carbonate 

 of potassa. From the Lebanon furnaces of the Messrs. Cole- 

 man, Mr. W. Fisher reports that the white deposit was chiefly 

 sulphate and muriate of potassa. The quantities deposited 

 may admit of their application in the saline arts. 



Vanadium in Iron. — Deck and Wohler (Ch. Gaz. vi. 298),. 

 who examined the refining slag of Stafi'ordshire, which has the 

 reputation of imparting ductility to iron when mixed with it, 

 found that it contained silicate of vanadic acid with minute 

 portions of molybdenum, chrome, and the usual quantities of 

 silicates and of phosphoric acid. 



Arsenic in Iron. — Schafhliutl has shown the almost constant 

 presence of arsenic and phosphorus in cast-iron, steel, and 

 bar-iron, and connects their observation with the late discovery 

 of both these elements in mineral waters, their ochreous de- 

 posits and iron-ores. He attributes the quality of the Dan- 

 nemora iron, and of the Low Moor iron (England) to their 

 content of arsenic, and the quality of some Russia iron to its 

 content of phosphorus. (Journ. f. Pr. Chem. xl. 304.) 



Alkalimetric Test for Iron. — According to Marguerite (Tech- 

 nologiste, 1846), the iron is dissolved as protoxide, and con- 

 verted into peroxide by a measured quantity of permanganate 

 of potassa of known strength, and the total conversion is 

 known by the liquid assuming a rose-red tint. The test liquid 

 is obtained by fusing a mixture of 1 equiv. chlorate of potassa, 

 3 eq. caustic potassa, and 3 eq. binoxide of manganese, ex- 

 tracting with a little water, treatment with muriatic acid, until 

 a violet-color appears, and then filtering through asbestus. 1 

 eq. permanganate of potassa is equal to 10 eq. protoxide of 

 iron. The iron test-liquid is prepared by dissolving 1 grm. 

 pure iron-wire in 20 cubic centimetres pure muriatic acid, dilut- 

 ing with 1 litre water and the permanganate dropped from a 

 graduated tube until the liquid assumes a permanent rose-red 



