1879.] on Ooining Silver into Rupees. 61 
assay, or is 0°116 milliéme. The usual daily check is one such report from 
a melting and 10 from single assays of coins, and, as the probable errors of 
these values are 0°116 and 0:114 respectively, it is evident that they are 
practically of equal weight: when so taken the probable error of the mean 
fineness of a day’s work wil] be 0:081 milliéme. 
In receiving Bullion about seven separately assayed parcels make a lac 
(1,00,000) of Rupees in value. The probable error of an assay report has 
above been found to be 0:087 milliéme and that of alac (in value) of Bullion 
3°29 Rupees from assay only. The probable error of a lac of coinage is 
81 Rupees from its assay, which shows that even for this small daily 
outturn, the valuation is not sufficiently good ; and the uncertainty increases 
in proportion to the outturn, while that of the intake does not increase so 
fast. 
» With 1 lac of outturn the probable error is 2°47 that of equal receipt 
2 ? PP) 3°50 ” ”? 
3 oP) » 4:27 oP) ”? 
4 ” ” 4-95 9 39 
Tn order that the assay valuations of receipt and outturn should be 
similar, the coinage should be only 63,600 Rupees daily. 
If these checks stood alone, it would be impossible for a Mint Master 
to feel any confidence in his work. And an assay establishment suffi- 
ciently large to value a heavy coinage thoroughly, and to make the 
necessary assays of single coins would be very expensive. The assays of 
_ pots are a very valuable test in a large coinage, especially when, as here, 
they are made nearly uniform in composition and thus check each other. 
In practice a coin beyond the legal remedy of two milliémes in fineness 
is almost unknown, but the law is now probably as exacting as it is 
possible to make it. d 
I am very greatly indebted to Mr. Edis, who was acting as Assay Mas- 
ter of this Mint, for the attention and skill he gave to these assays, which 
were more in number than the amount of work ordinarily would have 
called for. The accuracy of his work is proved by the small probable 
errors, : 
To obtain these data was the primary object of my experiments : incid- 
entally, however, the weighments which are made in passing the metal 
from hand to hand furnish some interesting information as to the general 
working of the Mint which I purpose here to place on record. 
The unit of weighment is a tolah (the weight of a standard rupee) of 
180 grains, which is here decimally divided: 8 tolahs are equivalent to 3 
ounces Troy; the English Pound contains 38°88889 and the kilogram 
85°73526 tolahs, And hence— 
