g6 PHILOSOPHICAL TRANSACTIONS. [aNNO ITQl. 



fire in which was 120° of Wedgwood's scale, it was found melted into a vitreous 

 p:ile bluish mass ; and the inside of the crucible was glazed yellow, with red 

 streaks, and had argentine spicuia adhering to it. 



Exper. 8. 800 grs. of the calcined antimony of Ex per. 1 were calcined for 8 

 hours in a dish, as in making Lile's powder, by stirring it constantly, and keep- 

 ing the bottom of the vessel red hot during the whole time ; the last 2 hours 

 also the whole of the powder was kept red-hot. On cooling, this calx was an 

 impalpable light-brown powder. 



(a) 100 grs. of this calx, triturated with an equal quantity of calcined harts- 

 horn, formed a powder very unlike James's powder, for it was of a light brown 

 colour. On exposing it to about I'iO" of fire, it melted into a yellow opaque 

 mass. 



(b) The remaining 700 grs. of the calcined antimony of this experiment were 

 exposed to fire and air, as before, for 8 hours longer, and kept red-hot a great 

 part of the time; but the calx became very little lighter coloured than before. 



(c) 100 grs. of this calx last mentioned (b), triturated with as much calcinated 

 hartshorn, being exposed to the degree of fire usually applied in making the 

 pulvis antimonialis, in a close vessel, the mixture melted partially into a greyish 

 mass. 



(d) 150 grs. of the calcined antimony (b) of this experiment were mixed with 

 an equal weight of calcined hartshorn. This mixture was raked about in an 

 earthen dish for an hour, during a great part of which time it was red-hot. On 

 cooling, the powder was evidently lighter coloured than before this calcination. 

 It was then exposed in a close crucible to a white heat for -i- an hour; and after 

 cooling a loosely cohering white solid, with a vitreous yellow coat, was found, 

 little inferior in whiteness, and otherwise resembling James's powder. 



(e) 300 grs. of the calcined antimony (b) of this experiment were raked about 

 in an earthen dish for an hour, a great part of which time they were kept red- 

 hot. On cooling, the calx was found of the same colour as before ; and after 

 exposing it in a close crucible in the melting furnace to almost a white heat for \ 

 an hour, it was observed to have been melted into a yellowish mass. 



It seems at least very probable, from this experiment, that no degree or dura- 

 tion of fire, applied in open or close vessels to antimony alone, can produce a 

 calx of the same kind as that in James's powder : nor perhaps can such a powder 

 be composed by fire applied, in close vessels, to calx of antimony mixed with 

 calcined bone ; but if antimony duly calcined be mixed with calcined bone, and 

 exposed to air, in a due degree of fire, for a sufficient length of time, and then 

 a still greater degree of fire be applied to it in close vessels, such a compound 

 may be formed as James's powder. I'his experiment also proves, that the sul- 

 phur in antimony is no ways necessary to the formation of this compound. 



