174 Dr Skene Keith on a New Instrument for Measuring 
only the same specific gravity, and Kirkudbright bigg of the 
second quality had a specific gravity of 1.265 ; nay, while se- 
cond Haddington barley that weighed 52.265 per bushel, is said 
tp have a specific gravity of 1.333; and third Linlithgow, of 
46.375 lb. per bushel, to have exactly the same specific gravity. 
According to the experiments which I have made, the best 
wheat has only a specific gravity of 1.333; while barley has a 
specific gravity of different degrees, according to its weight per 
bushel ; and Scotch bigg, though in all cases inferior to barley, 
even when of equal weight per bushel, (because it packs or lies 
closer in a measure, from its being a smaller corn,) has also a 
specific gravity that nearly corresponds to the relative weights 
per bushel of the different kinds which I submitted to trial. 
The following Table exhibits the comparative specific gravi- 
ties of five kinds of Scotch bigg, and as many of barley, which 
appear consistent with each other. 
1. Scotch Bigg of 41.713 lb. per Bushel, Specific Gravity, 1.067 \ MejcJium of five 
44.464 - - - 1.093^ kinds, — 
44.971 - - - L113 V 45.199 per bu- 
46.457 - - - shel, and 1.109 
48.390 - - - 1.146 ^ Sp. Gravity. 
2. Baulk v of 49.418 per busbel,. 
50.166 
50.652 
52.383 
53.243 
Specific Gravity, 1.173 > 
. Medium of five 
1.181 i 
r kinds, — 
1 
1 
H-* 
5 
51.172 per bo- 
1.227^ 
l shel, and Sp. 
1.242 
' Gr. of 1.205. 
The instrument with which these comparative specific gravi- 
ties were ascertained, consists of two pieces. The first is a brass 
cylinder of three inches diameter, and 
a little more than three inches deep, 
which was made to contain exactly one- 
hundredth part of a standard Win- 
chester bushel of barley. Three mea- 
sures of each kind of barlev and bigg 
were weighed ; and the medium of the 
three was multiplied by 100, as the 
average weight of a bushel. The second piece is a cover made 
to the first, like the lid of a snuff-box, ground so as exactly 
fo fit the cylinder, but raised in the middle. Three brass 
2 
