174 Mr. Hatchett’s Experiments on the various Alloys , 
From the result of this experiment it appears, that by the 
action of a soft powder, such as whiting, line gold sustained a 
greater loss than gold made standard by silver; and again, that 
this, being more ductile than any of the other kinds of standard 
gold, suffered more than those ; for it is evident, that the wear 
produced by this experiment, was in proportion to the softness 
or ductility of the pieces of metal, those which were compara- 
tively hard, being in general those which were the least abraded. 
In the same order also, the difference between plain and 
stamped surfaces was perceptible. 
It must be likewise remarked, that although copper, when 
rubbed against copper, experiences a much greater loss than 
either gold or silver, yet, when copper is exposed to the action 
of a powder like whiting, as in the present experiment, it is, on 
the contrary, the metal which is abraded in the smallest degree. 
Lastly, it may be observed, that this experiment fully proves, 
that the wear is much greater upon raised or embossed sur- 
faces than upon those which are flat and plain ; and that, in 
proportion to the ductility of the metal, the difference of wear 
between plain and stamped pieces becomes more apparent. 
The preceding experiment was made with a weight upon 
each piece, equal to gibs. 8 oz. 12 dts. and 21 grs. which was 
the same as was employed in every experiment made with the 
machine No. 1. But, previous to the following experiment, in 
which fine white writing-sand was used instead of whiting, 
it was found, after 5280 revolutions, that no inference could be 
made when this weight was employed ; for the sand soon 
began to accumulate upon the faces 5 f the pieces, and adhered 
like a dark gray or blackish crust, which with great difficulty 
was detached. In consequence of this, the wear of the pieces 
