Section of Chemistry and Electricity. 407 



The general saving on the average he stated to be no more than 

 10*. per ton, and observed, that the price of such iron in the market 

 had actually fallen from 15*. to 20s. per ton, while that from cold air 

 at the same time rose 5s. per ton in Yorkshire. (This statement gave 

 rise to observations on the part of several gentlemen, who dissented 

 from Mr. Hartop, and stated that the reduction in price of iron 

 from hot air had not occurred in other parts of the country, and 

 that, as prepared in Glasgow and many other places, it had not been 

 so deteriorated. It has in consequence been adopted in every 

 smelting-house in Scotland, and the annual produce of the works 

 in that country during the last ten years has been nearly doubled. 



Reference was also made to processes adopted in the Russian 

 smelting-works, which showed that by a judicious adjustment of the 

 quantities of cold air introduced by the blast, a saving could be ef- 

 fected approaching even to that obtained by the use of hot air.) 



Account of some Chemical Processes. By Francis Barker, M.D., 

 Prof. Chem. Trin. Coll. Dublin. 



It has been known since the time of Bergman, that diluted acetic 

 acid has little or no action on peroxide of iron ; but it is not, per- 

 haps, generally known that this oxide may be completely separated 

 from sulphuric or muriatic acid, and probably from most other 

 acids, by an alkaline acetate, the alkali exerting its usual action of 

 detaching the peroxide, whilst the acetic acid remains inactive and 

 does not unite with it, and that by means of the acetate of potash, 

 peroxide of iron may be completely detached from the oxide of 

 manganese, one portion of the acetate of potash decompounded by 

 the salt of manganese producing acetate of manganese, which re- 

 mains in a state of solution, whilst the other portion of the acetate 

 of potash separates the peroxide of iron, on which the diluted acetic 

 acid has no action. The advantages arising from this mode of 

 operating are obvious, as it gives the chemical analyst the means of 

 separating the oxides of iron and manganese by agents easily ob- 

 tained and in the hands of every chemist. 



As the success of this method depends in a great measure on at- 

 tention to minute details in the mode of conducting the process, 

 more especially on the comparative quantities of the substances em- 

 ployed, a few experiments are adduced. 



Experiment. — Five grains of green sulphate of iron taken and 

 dissolved in fifty measured grains of cold distilled water : to this 

 added, from the end of a dropping-tube, six drops of diluted nitric 

 acid, spec. grav. 1*280. On applying heat to this mixture, it ac- 

 quires a dark olive colour, arising from decomposition of the nitric 

 acid by the protoxide of iron and absorption of the nitric oxide by 

 the ferruginous solution. When the mixture is heated to ebullition 

 this colour disappears, and is succeeded by the ordinary yellow co- 

 lour of a solution of peroxide of iron. To the solution of the sul- 

 phate of iron, thus altered by the action of nitric acid, an aqueous 



