568 
MR. W. 0. D. WHETHAM ON THE ALLEGED SLIPPING 
Tube No. 3. 
9 , 0'0"; finish 15'28"-0 . . . 15'23"-0. 
Pressure .—Gauge scale, adjusted at start to 22 ' 00 , reading at finish 2 1 A/. 
Kathetometer readings— Start |^ 2 . 5 g 3 | 22'682 
22-956. 
Temj)erature readings at intervals of two minutes— 
13-00 12-88 12-86 12-90 12-92 12-93 12-95 12-98 . . 12°-93. 
In order to make the pressure readings strictly comparable, the level of the water 
before each experiment was adjusted to a mark, m, in the top bulb, and after each to 
a mark ra in the lower bidb, and all pressure readings were taken while the water 
stood at these levels. The pressure was adjusted by the pump till the reading on the 
gauge scale was as nearly as possible 22 - 00 , and the exact height then read off by a 
telescope in terms of kathetometer scale. 
Tuhe No. 1 .— (r = ’042 cm. ; I = 27-30 cms.) 
Total difference of pressure equivalent to about 250 cms. of water column. The 
limiting pressure is 305 cms. 
Pressure. 
Temperatui’e. 
Time. 
Unsilvered. 
mm. 
1. Gauge reading .... 
407-1 
12-59 
12 25-7 
2. ,, ,, .... 
407-0 
12-71 
12 24-1 
Silvered. 
3. Gauge reading .... 
407-1 
12-79 
12 23-5 
The temperature correction is 2-22 per cent, for 1 ° C., and in order to correct ( 2 ) to 
12°-79, we must subtract l"-4. 
The pressure correction is for 0-1 mm. of sulj)liuric acid in a total pressure equivalent 
to about 1400 mm., i.e., 1 in 14,000, and is therefore negligible. 
The weight of silver deposited is 0-0008 grm., and the thickness 0 00001 cm., a 
change in of 0-1 per cent. 
/ // 
The time for the unsilvered tube corrected = 12 23-41 
,, „ silvered ,, observed = 12 .23-51 
