On the 'MamifaSlurc of Pig-Iron icith Pit-C<^al. 35 



boiled, the gas feparates from the mercury ; and the exccfa 

 of nitrous acid, whicii always comes over with nitrous ether, 

 deconipofes the ammoniacal muriat, and forms corrofive 

 mercurial muriat or fublimate. This theory is corroborated 

 by comparing the quantity of gas eftimated to be contained, 

 in the fulminating mercury, with the quantities of gas yielded 

 from alcohol and nitrous acid, with and without mercury in 

 folution ; not to mention that more ether, as welj as more 

 gas, is produced without the intervention of mercury ; and 

 that, according to the Dutch chemifts, the produil of ethef 

 is always in the inverfe ratio to the produ6l of nitrous ether- 

 ifed gas. Should a further proof be thought neceflliry, of 

 the exigence of the nitrous ctherifed gas in the fulminating 

 mercury, as well as in the white denfe fumes, it may be 

 added, that if ia mixture of alcohol and nitrous acid holding 

 mercury in folution be fo dilute, and expofed to a tempe- 

 rature fo low, that neither ether nor nitrous etherifed gas are 

 produced, the fulminating mercury, or the white fumes, will 

 never be generated ; for, under fuch circumftances, the mer- 

 cury is precipitated chiefly in the ftate of an Inflammable ox- 

 alat. Further, when we coufider the different fubflances 

 formed by an union of nitrous acid and alcohol, we are fo 

 far acquainted with all, except the ether and the nitrous 

 etherilcd gas, as to create a prefumption, that no others are 

 capable of volatilifmg mercury, at the very low temperature 

 in which the white fumes exift, fince during fome minutes 

 ihey arc permanent over water of 40'' Fahrenheit. 

 [To be conducted in the next Number.] 



III. On ihe Origin and Progrcfs of the ManufaBure of Pig- 

 iron uiitk Pit-Coal; and Cofnpari/on of the f^'alue and 

 Effe.'fs of Pit-Coal, J Food, and Peat -Char. By 3Ir. 

 David Mushet. 



A, 



-FTER the former communications, relative chiefly to 

 the manufacturingof pig-iron with pit-coal, it may not be 

 amifs tn make a few general obfcrvalions ;js to the origin of 

 the procefs, the different modes of condu(!-ling it, and, bv 

 drawing a comparifon between the refuils obtained at various 

 F z period:-, 



