VOL. XII.] PHILOSOPHICAL TilANSACTIONS. 427 



In both which meltings such a heat was given, as made all of a clear light 

 red heat. Then the pot was taken off, and all permitted to separate, settle, 

 and cool in it. On breaking the pot the regulus of gold, being very distinct 

 in the bottom, and easily separated from the antimony, weighed J 63 grains. 



This way of cooling all in the pots was observed in all the following ex- 

 periments, for the more certain separation and settling of the regulus, with- 

 out effusion into the antimony-horn, or hollow iron-cone. Which effusion, 

 by confounding and cooling the mixture, may be some hindrance to a more 

 perfect separation. Note also, that borax was used in every pot, for prevent- 

 ing the sticking of the regulus to the bottom, and the antimony to the sides 

 of it. 



A piece was broken off the regulus, which weighed 38^^ grains, and was 

 kept to be refined on the cupel apart. The weight of the remainder was there- 

 fore 1 24-^ grains. This remainder being powdered, and put on an equal quan- 

 tity of fresh antimony, as at first, and melted down, the regulus weighed 74 

 grains. 



The other piece, of 3 84^ grains, being refined on a cupel from the antl- 

 monial substance mixed with it, by exhalation, promoted sometime with a 

 blast upon it, especially toward the latter end, as in all the following experi- 

 ments of refining upon the cupel, weighed 304- grains : and upon melting with 

 borax in a crucible, lost not above half a grain. So that the weight of the 

 whole to the gold it held, was as 38-i- to 301, or the gold almost -§- of the whole. 



The latter regulus, weighing 74 grains, being refined in the same manner, 

 weighed 63 grains : the gold holding in proportion to the whole, as 63 to 74, 

 that is near upon -f of the whole. So that the same regulus of gold and anti- 

 mony, in passing through new antimony, though it lose much in weight, yet 

 there is not a proportionable loss of gold : but it is richer in gold, as is proved 

 by this and many other trials. 



Both the parcels of antimony being saved, for separating the gold remaining 

 behind in them; they were severally mixed with equal weight both of tartar 

 and nitre, and then fired, and so reduced to a regulus. Then the regulus of 

 each, exhaled and blown off upon cupels. Of the first parcel of antimony, 

 with which the gold was first melted, the regulus being exhaled, there re- 

 mained in gold 30 grains. Which, upon melting in a crucible, lost scarcely 

 half a grain. Of the second parcel of antimony, with which the first regulus 

 of gold and antimony, weighing 1241 grains, was melted, there remained in 

 gold 27 grains. 



All the other parcels were fine gold to sense, on the touch. Only that out 

 of the first antimony, was apparently not fine, and pale, from the silver in the 



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