191 
PROCEDURE, SERIES I.—F or this series of measurements the tube A was 
kept at steam temperature, while the tube B was packed in melting ice. 
The tubes were first carefully cleaned, washed with acid and alkali solu- 
tions, rinsed and dried, then mounted in place as in Fig. 2. Dry air free 
from CO. was drawn through them for some time, meanwhile gently 
warming them with bunsen burners. A small amount of the quartz powder, 
previously heated and cooled in a dessicator, was introduced, and the dry 
air suction continued for some time. The apparatus was thep rocked and 
tilted as described above in order to effect a proper distribution of the 
powder, steam was admitted about A aud the ice bath placed about B. 
After a period ranging from one to two hours, with both tubes open to 
the atmosphere through the drying train, the glass rod was rubbed, the 
temperatures and atmospheric pressure were observed and the steam and 
ice baths were withdrawn. After some hours the figures were measured 
in the manner above described. The thermometers used were frequently 
compared with standards, and the temperature in the steam jacket was 
constantly checked from Standard barometer readings. One complete set 
of average wave tength measurements-is given in table I, and the data for 
eight such experiments, together with calculated values of ko are 
ky 00 
given in table II. 
Tube A, in Steam. \ Tube B, in Melting Ice. 
55.43 y, 63.73 2 
93.50 38.07 96.47 32.74 
132.13 38.63 129.23 32.76 
170.37 38.24 162.03 32.80 
208.80 38.43 194.50 32.47 
246.80 38.00 | 227.60 33.10 
285.13 38.33 260.80 33.20 
323.47 38.34 293.77 32.97 
361.60 38.13 | 326.03 32.26 
399.95 38.35 | 358.97 32.94 
438.17 38.22 391.63 32.66 
476.23 38.06 424.93 32.30 
514.33 38.10 457 87 32.94 
553.10 38.77 | 490.50 32.63 
591.20 38.10 523.10 32.60 
| 556.00 32.90 
589.17 33.17 
Most probable value of Most probable value of 
A = 38.262 mm. + 0.01, _= 32.838 mm. + 0.01, 
Oh 0!225 IM. er— 0279 
lable 1. 
