Dr Skene Keith on the Final Report of the 
the standard Troy pound of 5760 grains, which has been for 
many centuries the legal weight of England, though it is larger 
than the old Tower pound of London. 
But though I highly approve of those great articles, I must 
object to some other parts of their report, while I assign my rea- 
sons for differing from them in opinion, and state some facts 
which may merit the public attention. It is the peculiar advan- 
tage of mathematical science, and shews its great superiority 
over logical discussion, that its truths can be clearly demonstrat- 
ed, and that where there is any, the quantum of error can often 
be accurately ascertained. Yet it should always be remembered, 
that as Achilles could be wounded in the heel, so a mathematician 
is vulnerable in his data. Therefore, I observe, concerning 
the temperature at which these standards were fixed, and are 
afterwards to be verified, — namely, 62° of Fahrenheit, that this 
degree of heat does not appear so proper, as if it had been fixed 
at 40°, or 394°, the temperature at which water is most concen- 
trated, or occupies the least volume. In the days of Sir Isaac 
Newton, 50° was reckoned the standard of moderate tempera- 
ture. About sixty years ago this was estimated at 55°, which 
still continues to have the mark of temperate affixed to the scale 
of our thermometers. But in 1790 and 1792, in the very ac- 
curate experiments of Sir Charles Blagden and Mr Gilpin, 60° 
was assumed as the standard of temperate heat, while they as- 
certained the specific gravity of ardent spirits of various degrees 
of strength, and from 30° to 80° of Fahrenheit’s thermometer. 
Of late, this standard has been raised to 62° ; or that degree at 
which it is said one feels comfortable in a room ; and, in the 
progress of luxury, it may rise to 70°. But as there is a parti- 
cular degree of heat, at which water occupies the least bulk, — 
as distilled water of 40° is extremely near, in point of specific 
gravity, to common water of 60° or 62°, as different thermome- 
ters, and difierent degrees of temperate heat are used in different 
countries, and by different persons, and as it was ascertained by 
Mr Everard and a Committee of the House of Commons in 1696, 
that an English cubic foot of common water of a moderate tem- 
perature, contains very nearly 1000 Avoirdupois ounces, (only 
10.4 grains less, or exactly 437439.4 grains), I cannot help think- 
