122 Mr. Hatchett’s Experiments on the various Alloys , 
Experiment n. 
Eleven ounces one pennyweight and two grains of gold* 
23 car. 3^ grs. fine, were alloyed with nineteen pennyweights 
and six grains of copper; the whole being well melted, was 
stirred with a large earthen stirrer ; and, in order the better 
to mix the alloy with the gold, the melted metal was poured 
alternately into two red-hot crucibles, after which, it was cast 
in the mould of iron. The rough end of the bar was cut off, 
and a piece was then taken from each extremity. 
The specific gravity of the upper end was - 17,035 
And that of the lower end was - - 17, 364. 
So that, according to this experiment, the bottom end of the 
bar possessed the greatest specific gravity, contrary to the results 
of the former experiments. 
By an assay of each piece, made by Mr. Bingley, it how- 
ever appeared, that this difference in specific gravity was not 
caused by any unequal quality of the gold, for the proportion of 
alloy in the two pieces was found to be precisely the same ; the 
alloy had therefore been uniformly mixed. 
Specific gravity. Quality by assay. 
1. Top - 17,035 - Better than standard, by 8 grains Troy. 
2. Bottom 17,3^4 - Better than standard, by 8 grains Troy. 
It now remained, therefore, to examine whether the copper 
alloy, which was thus regularly distributed throughout the mass* 
could again be induced to separate by a subsequent fusion. 
Experiment nr. 
The bar which had been made in the preceding experiment, 
was again melted, and was kept in complete fusion during half 
