STOVE FOR HEATING AND DRYING. gf)3 



salt by the heat of ebullition, that injures the lixivia for pre- 

 paring prussian blue. 



The simple prussiate assumes the character of triple prus- Sim pl e prusst* 

 , , , . , . , .,,.., ate converted 



siate, as soon as black oxide ot iron, or a salt with this oxide i nt0 triple, 



for its basis, is presented to it; and thus acquires, beside the ■ 



advantage of being crystallizable, that of not being decom- 

 posable at a boiling heat. 



This prnssiate, which was the test liquor so much sought Thetestliquor. 

 after by chemists, does not afford prussian blue with solu- 

 tions of red oxide of iron ; but it produces this blue if they 

 contain any black oxide, because its acid immediately at- 

 taches itself to that portion of the black oxide, which will 

 serve as an intermedium between it and the red oxide. 



The triple prussiate of iron, or prussian blue, strongly Decompose 

 heated, is reduced to ammonia, carbonic acid gas, gaseous tlon of tlie trJ ; 

 oxide of carbon, steeled iron, and carbon. iron) 



The prussiate of mercury affords the same products by its & of mercury# 

 decomposition, and likewise a certain portion of oil. 



The lixivia of the carbonized materials contain little triple The ^^j- 

 prussiate, but a great deal of the simple ; and they muft not 

 be boiled down, till the constitution of the second is strength- 

 ened by ail addition of black oxide, or of green sulphate. 



To obtain from these lixivia all the prussian blue they are How to obtain 

 capable of affording, it is indispensably requisite, to employ a J^™™*^ 111 * 

 sulphate of which a portion at least is green; without which 

 the simple prussiate they contain cannot furnish blue with a 

 sulphate of which the base is completely red. 



To conclude, if the reader take the trouble to compare 

 this paper with Scheele, he will find, that all the truths it 

 contains were perfectly known to him ; but I conceived they 

 required to be more fully explained, which I have here at- 

 tempted. 



III. 



An Account of a Stove for Heating Rooms, or Drying different 

 Articles; by Mn G. Field, of Newman-Street.* 



JL HE various advantages of heating, boiling, steaming, 



evaporating, drying, ventilating, &c, are united in this stove ; 



so' 

 * Transactions of the Society of Arts, for 1806, 



