: 
‘ 
; 
: 
4 
: 
of bars at the temperature of melting ice. 455) 
Mean differences of Zine and Stéel bars. 
| Zy — 5; Remarks. 
(geen F 
Me + 12°2+2°8 Before heating Z,. 
P.M. + 90+40°5 
+ 99+40°5 
31 + 10°4+40°4 
Feb. 2 + 1491407 After heating Z, to 208° F.. 
3 A.M. + 1166404 Z, remained constantly in melting 
P.M. +112:°340°8 ice from 8.45 P.M. Feb. 2d to. 8.21 
4 A.M. +103 340° P.M. Feb. 6th. 
5 PLM. +100°14+1°0 
6 +100°44 0-4 
vi + 95°341°8 
8 + 98°2+40°5 
9 +101°040°8 
10 A.M. — 21°240°7 After cooling Z, to about ~8° F. 
10 P, Me. —~ 185405 Z, was in melting ice from morn- 
11 A. M. — 20140°4 ing of Feb. 10th to evening of 
12 P.M. — 55407 Feb. lith. © 
13 + 211402 After heating Z, to about 70° F. 
the comparisons of January 28th showed larger residuals than 
any subsequent set of comparisons. The comparisons of this 
Before packing it in ice on January 28th, the zinc bar had been 
or many months warmer than 32° FP. 
time it shorten , leaving it still 90" longer than its initi 
length. Exposure to the air of the comparing-room (tempera- 
ture about 45° F.) during the intervals between comparisons 
then warmed to the temperature of melting ice. This dimin- 
