o^' THE .MEASUREMENT OE TEMPERATURE. 
J l^! 
7. Tlte Ccdibrafion of the Biilh. 
Tlie volume of the hulh was (letenuined by weighing it empty, ami afterwards 
tilled with water at the melting-point of ice. A glass tube was connected with the 
stem by a piece of rubber tube to prevent loss of water when the temperature rose. 
The followino- are the results :— 
O 
(a.) 
(/,.) 
AA'eight of Imlb empty. 
71 -9051 
71-9568 
,, ,, ,, filled with water at 0” C. to division 12G on stem 
170 •6Gr)7 
170-GG57 
AA'eight of catch water. 
4 • .j8.3G 
4•5860 
,, „ water. 
94-12.30 
,, „ ,, corrected for weight of air in hull), Ac. 
94-1975 
AMlume of bulb to division 70 at 0° C. 
94 209G 
The coefficient of expansion of the glass of which tlie thermometer bulb was made 
was determined bv the weigiht-thermometer method. The weio-lit-thermometer was 
v' Co O 
made from the same glass tube as the thermometer hull). The value for the 
coefficient was found to be 0’0000285. 
^ The composition of the glass employed, which was obtained fiom Messrs. C. E. 
Muller k Co., of High Holljorn, appears to be very constant ; for the coefficients 
of expansion of samples of it determined by Kuenex and Randall {loc. cit., p. 109) 
in 1896, and bv one of us in 1901, have the same value as that last determined. 
The change of volume of the bulb due to change of the pressure on the gas Inside 
it was also measured. It vas determined by filling the bulb with water to a point on 
the stem and measuring the change in the position of the meniscus when the })ressure 
was reduced by means of a water ])ump. The change of volume amounted to 
0'0017 cut), centim. per atmosphere. 
8. 'Ihe Deetd-Space. 
Both tdiAPPUIs and OxNEs em])loyed a glass tube with a steel cap attached to it 
by cement, and enclosing a steel point for the adjustment of the mercury meniscus. 
In tlie construction of our instrument we have entirely dispensed with steel and 
cement connection, and have employed an opaque glass point e sealed into the tube 
f, which formed the dead-space at its point of junction with the stem. The tube for 
the dead-space was cut from a piece of glass tube of 9 millims. internal diameter, 
selected for its straightness and regularity of bore ; the manometer tube cj was cut 
from the same piece. In making the junction with the capillary tube great care was 
VOL. CO.-A. Q 
