J50 -EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 



This experiment proves, 

 Verydufltlc id. That very du^ile nanciard gold, when expofed to the 



and harder gold friction of gold of a fimilar quality, faffers lefs by abrafion than 

 compared. ^^^^ ^^.^^^ .^ comparatively brittle, or harder, and which is 



fubjeaed to friaion under the fame circumftances. 



2d. Thai when foft gold and brittle or hard gold rub 

 againft each other, the greateft lofs is fuftained by the foft 

 gold. And, 



3d. That pieces which have raifed or emboffed furfaces, 

 fuffer a greater lofs, under every circumftance, than thofe 

 which are fmooth and fiat. 

 Coinrubb'ng The whole of the foregoing experiments were made with 



againft con, in ^j^^ machine called No. 1 ; and, as the friaion was conti- 

 htiiX'^ Wes but nued, in each experiment, during many days, with a prefTure 

 liule. upon each couple of pieces equal to 3 lbs. 8 oz. 12 dts. and 



21 grs., and as (confidering the feverity of fuch a trial) the 

 lofs fuftained by the pieces, feparately or colleaively, was 

 not very confiderable, it may with reafon be inferred, that 

 ftandard gold does not eafily fuffer abrafion by the friaion of 

 metal againft metal, or of coin againft coin, efpecially under 

 the circumftances which commonly prevail during the circula- 

 tion of money. 



In the machine No. 1, the pieces of gold were oppofed 

 face to face ; it now therefore appeared proper, that the faas 

 thus afcertained concerning the wear of gold, of different 

 degrees of duaility, Ihould be farther examined, and corro- 

 borated by a different method. To effea this, the fecond of 

 the machines before defcribed, was employed. 

 Experiments 'pvvo hundred pieces of gold, of five different qualities, 



No.' 2?''^^'"^* were employed in this experiment ; twenty pieces of each 

 kind were plain and fmooth, the others were ftamped with 

 the die already mentioned. The two hundred pieces were 

 mingled, and were enclofed within the cubic box. 

 Different ^uali- The following were the qualities of the gold. 1. Gold of 

 ties ot ihe gold. 2^ ^^^ ^^ ^^^^ 2. Gold made ftandard by filver. 3. Gold 

 made ftandard by filver and copper. 4. Gold made ftandard 

 by fine Swedifh copper. 5. Gold made ftandard by equal 

 parts of fine Svvedifli copper and dollar copper. 



After 71720 revolutions of this machine, performed in 40 

 hours, the lofs fuftained was found to be as follows : of No. 1. 



the 



Their lofs. 



