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But the lime I ufed was pure and perfedly free from fixed air ; 

 can that be faid of the common lime of Marly, which he employed 

 and does not fay he had prepared ? Befides, by his edulcorations, 

 much pure lime muft have been diffolved, and have mixed with 

 the folution of muriated lime, and if his alkali were not cauftic, 

 the quantity of lime precipitated by it muft have been at leaft par- 

 tially aerated, and confequently the mere earthy part apparently 

 greater than it would have been if pure. However, as this expe- 

 riment forms a cumulative proof both of the proportion of acid 

 contained in fal ammoniac, and of the quantity of it taken up by 

 a given weight of lime, I thought it incumbent upon me to repeat 

 it, hence I mixed 50 grains of fal ammoniac with 150 of flacked 

 lime, and heated the mixture in a large glafs phial until all the al- 

 kali was driven off and the mixture ceafed to fmell, I then added 

 a fufficient proportion of water, and digefted the whole in a gentle 

 heat for fome hours, then filtered and edulcorated the mafs on the 

 filter, as I judged the folution to contain lime as well as muriated 

 lime, I palled a flream of fixed air into it, which inftantly turned 

 it milky, and then filtered it off; the folution now free from lime 

 I precipitated by a folution of an aerated foda, which contained 

 1 7 per cent, of fixed air, as much of the folution was requifite as 

 contained 123 grains of foda. The precipitate colleded, edulco- 

 rated and dried for fome hours on the filter, in a heat of 150'^, 

 weighed 46,75 grains, though no more could be feparated than 

 41,62, thefe after ignition weighed 35 grains, fome ftuck to the 



glafs 



