150 Mr. Hatchett's Experiments on the various Alloys , 
Table I. 
Total number of revolutions, 200300. 
Quality. 
Weight be- 
fore friction. 
Weight after 
friction. 
Loss. 
1. Gold made standard by 
copper 
Grains. 
844,90 
Grains. 
844,90 
Grains. 
2. Gold reduced to 18 carats 
by copper 
747,60 
747,6° 

3. Gold made standard by 
copper and silver 
829,20 
829,10 
,10 
4. Gold made standard by 
silver - - 
93 7 > 2 ° 
937 > 10 
,10 
5. Gold 23 car. 3^ grs. fine 
00 
b 
849,80 
4,20 
6. Gold made standard by tin 
and copper 
846,90 
831,60 
15,30 
7. Gold made standard by 
iron and copper 
825,10 
803,50 
21,6o 
8. Gold alloyed with an equal 
proportion of copper - 
615,68 
549 ’ 9 ° 
65,78 
According to this statement, it appears, that fine gold of 
23 car. 3-^ grs. suffered more by friction, under the above 
described circumstances, than gold made standard either by 
copper, by silver and copper, or by silver ; but that this fine 
gold of 23 car. 3^ grs. suffered less by wear than gold made 
standard by tin and copper, or by iron and copper ; and, lastly, 
that copper, although it appears to be beneficial when in the 
proportion of and sometimes when it even amounts to T 3 -, 
yet, if employed in a larger proportion, for example, when equal 
to the quantity of gold, it then becomes highly detrimental, 
