176 Dr Skene Keith dfaa New Instrument for Measuring 
of each other ; and the Avoirdupois pound was found to contain 
7000 of these Troy grains, but is fully a grain weightier than 
the standard Avoirdupois pound. 
It cost this ingenious man much trouble to make a medium 
Troy pound and grain, from the inequalities of the standard 
weights ; and he was poorly paid with a load of oatmeal which 
I gave him for his labour. 
The brass bushel was also made by William Spring in 1804 ; 
but I first got one top or lid, which was flat, and did not an- 
swer so well, and then the present lid, which is raised in the 
crown, by a watchmaker in the burgh of Inverury. I may yet 
get some improvements made upon it ; but the principal method 
here described is new, and has all the advantages of a hy- 
drostatic balance, while it ascertains the specific gravity of not 
one , but of a multitude of small articles, such as grains of corn. 
It is obvious, that a bushel of barley, bigg, or any kind of 
corn, contains, first the farina, secondly the hull, and, thirdly, 
the quantity of atmospheric air between the interstices of the 
corn. Whatever, therefore, has the highest specific gravity of 
farina, cateris paribus , must yield the greatest quantity of ex- 
tractive matter, and is the most valuable kind of that species of 
corn. 
I must add, that an equal portion of time, viz. three minutes, 
was allowed in each of the experiments, to prevent the absorp- 
tion of water in unequal degrees by the corn which was mixed 
with it. 
When it is considered, that Scotch bigg is so decidedly infe- 
rior to barley, in point not only of the climate in which it is 
raised, and of the relative quality and quantity of extract in the 
brewery, ardent spirits in the distillery, as well as the price 
which it brings in the market, when saleable, (which at present 
it is not), but also that the specific gravity of the individual 
corns is inferior to barley in a still greater proportion than its 
weight per bushel, I cannot doubt that the Legislature will 
agree to impose no higher a tax than what is proportioned to its 
ability to pay to Government. The nation must pay taxes ; 
let them only be proportioned fairly. 
If I make any improvements on the instrument which I 
have invented, I shall take the liberty of communicating them 
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