598 PEOF. J. J. THOMSON AND MR. Ct. F. C. SEARLE ON THE RATIO OF THE 
Diameter B. 
Calipers. 
25-4 cm. 
Left-hand screAv. 
Right-hand screw. 
Left-hand screw. 
Right-hand screw. 
(1) 
1-1701 
1-3843 
1-1793 
1-3787 
(2) 
1-1873 
1-3762 
1-1614 
1-4032 
(3) 
1-1268 
1-4415 
1-1150 
1-4485 
(4) 
1-8703 
0-6891 
1-8875 
0-6620 
Bottom end. 
Diameter A. 
Calipers. 
25-- 
1cm. 
Left-hand screw. 
Right-hand screw. 
Left-hand screw^ 
Right-hand screw. 
(D 
(2) 
1-43.52 
1-0999 
1-4289 
1-1209 
1-4734 
1-0699 
1-4918 
1-0586 
Diameter B. 
(D 
Calipers. 
25-4 cm. 
Left-hand screw. 
Right-hand screw. 
Left-hand screw. 
Right-Land screw. 
1-6109 
1-6978 
0-9270 
0-8427 
1-6131 
1-7106 
0-9385 
0-8371 
Taking the mean of these and correcting for temperature we find 
Top end . Diameter A = 25'4154 cm. 
Diameter B = 25’4056 cm. 
Bottom end Diameter A = 25'4125 cm. 
Diameter B = 25'4122 cm. 
Mean of these. . . . = 25'41]4 cm. 
]\[easurement of the Length of the Cglindcr. 
The length of tlie cylinder was transferred from the cylinder to the reading micro¬ 
scopes by means of the lieam compasses of the laboratoiy; care being taken to keej) 
the bar of the compasses parallel to the length of the cylinder while setting the 
compasses to the length of the cylinder. 
On account of the leno-th of the cylinder it wa.s found difficult to ascertain by 
