^ ( 337 ) 
that to which the other Metal, though Copper, depceffed it, 
was, bymeafure, aboat an Inch and three quarters ; fo that it 
is not every fuiall variation of Circumftances that can makeic 
doubtful to him that employ sour Inftrument, whether a Guiny be 
true or counterfeit. 
But Philofophical Candor forbids me to conceal, that there 
may, (though 'tis like there very feldom will, ) happen a cafe^ 
wherein, though the Principle, our Inftrument is framed on,wili 
bold good, yet the praflical Application may be unfecure. For, 
if a Falfifier of money have the skill, by waflimgor otherwife^ 
to take off much of thequantity or fubftanceof the Guiny with- 
out altering or impairing either the figure or the ftamp,the piece 
of Coin will not be able to deprefs our Inftrument to the ufual 
mark, and may thereby make it be judged c<?^»^^r/^/>, when 'tis 
Indccdhut too light. 
But on this occafion 'tis to be confider'd, that neither the 
Touchftone, nor Aqua Fortis, nor Antimony, nor the Cupel^ 
canlliewus, whether a piece of Coin proposed have its juft 
weight,but only,whetherthe Metal be true Gold : And therefore 
our Inftrument need not pretend to do more than difcover the 
Genuinefs of the Metal; but whether the Coin iiave the juft 
weight the Law requires, is to be judged by the Ballance; as 
each fingle piece is woat to be in moft of the Gold-Coins of 
rope^ and is in EngUnd in reference to jingels and twenty jhillwg 
Feices^ and all the other Coins of Broad Gold^ as they are now 
called. And yet it may be further confider'd, that our Inftru- 
ment does more than it need pretend to: For, without a pair of 
Scales, it prefenrly fliews, that the proposM Gumy, if it be not 
counterfeit, is otherwife abufed ; and though it does not clear- 
ly determine, whether that likewife proceed from cLe want of 
fpecifick Gravity in the Metal, or from the Coins having been 
waflied or otherwife fraudulently lefTen'd; yet it prcUhly re- 
folves the doubt, becaufe, if the want of weight appear by the 
Inftrumenc to be very great, asitufually does where the piece 
Y has 
