VOL. XII.] PHILOSOPHICAL TRANSACTIONS. 4^9 



over into the fire. It is not improbable also, that some loss of gold may take 

 place on the firing of the antimony, for reducing it to a regulus with tartar and 

 nitre, which make a vehement conflagration with much sparkling. 



It has been suspected, that some gold may be dissipated by the blast on the 

 cupels, in refining it from the antimony remaining in it. But this is not so 

 probable ; because gold has been melted several times with a greater proportion 

 of regulus of antimony simple, than is contained in the golden regulus, and 

 refined from it with the greatest heat and blast that could be given, without any 

 loss. And it is the constant practice of some refiners, to give their fine gold 

 a higher colour for gilding, to put a third or fourth part of crude antimony, or 

 of regulus of antimony, and with a great heat and strong blast work it off; 

 in which operation, in some ounces of gold, they lose not one grain. 



II. Again, there was taken 141-i- grains of crown gold, which was melted 

 with 1 ounce and ^ of antimony. The regulus w^eighed 123 grains. From 

 this, a piece weighing 30 grains was broken off, and resented for refining by 

 itself ; the remainder, being 93 grains, was melted down again with the same 

 antimony, being pow^dered and put on the top : and then the regulus came 

 forth, weighing Ql grains : so that here was no considerable loss. And there is 

 ground to suspect, that it might be upon some accidental difference in the 

 managing, that the regulus did not so perfectly separate and settle : for in all 

 other experiments of melting the same regulus again with the same antimony, 

 the regulus gained weight ; as in the next following : — 



From this second regulus, a piece broken off, and reserved for refining 

 apart, weighing 36 grains ; the remainder, being 53 grains, was melted down 

 as the former, and in the same antimony. Whereupon the regulus came forth 

 in weight 72 grains ; 17 grains being here gained to 55 grains, making the 

 whole 72 grains, i. e. between 4- and -i-. 



The first piece of 1 pennyweight and 6 grains, being refined on the cupel, 

 produced of fine gold 1 pennyweight just : which holds in proportion as 

 24 to 30. So that it contains a of gold, and but ^ of antimonial substance 

 in it. 



The second piece, weighing 36 grains, being refined on the cupel, produced 

 of fine gold 28 grains, in proportion of 28 to 36, which is rather less than 

 jl, as in the former; but the difference is inconsiderable for quantity. 



The regulus, upon the third melting, weighing 72 grains, refined on the 

 cupel, produced of fine gold 55 grains. This holds in the proportion of ^ : 

 but somewhat short of the former. 



On these comparisons, in this experiment of repeating the melting of the 

 regulus with the same antimony, the regulus gains weight each time, but is in 



