3 S 
Captain Kater’s account of the 
the steel plates to which the stirrups are attached coincide 
with the ends of the knife edges, otherwise some error 
might arise from a possible want of parallelism. 
The bushel measure being placed in one of the scales, 
together with 80 lbs. * the whole was counterpoised with 
brass ; the 80 lbs. was then removed, and the bushel filled 
with water by means of a syphon. The temperature of the 
water was then very carefully taken, and the height of the 
barometer registered. A circular piece of plate glass, as 
plane as could be procured, having a hole about a quarter of 
an inch diameter in its centre, was slid over the bushel, and 
the air-bubbles which appeared on the under surface of the 
glass were removed by touching them with a small bent 
tube made of flexible metal, a method thought of by 
Mr. Bate. Water was added through the hole in the glass ; 
and by carefully observing the curvature of the fluid surface, 
it was soon evident that the filling of the bushel might be 
repeated without a greater difference than three or four 
grains. 
It is scarcely requisite to remark that many experiments 
were made, not here detailed, before the adjustment of the 
bushel was perfected ; the very great accuracy and masterly 
workmanship however of Mr. Keir, who had been furnished 
with gauges for the diameter and depth of the bushel, ren- 
dered little alteration necessary. 
* This was obtained by taking twice the weight of the four weights of the 
gallon of. water. 
