72 
ROYAL SOCIETY OF CANADA 
employed for a period of five minutes for each charge, and for this period 
and 
instrument the specific conductivity is given by the formulæ— 
x = (log Va — log Vb) x 16 x 10 
where Va and Vb are the potentials at beginning and end of the 5- 
minute period, and 16 x 10“ is a constant for the instrument for a 
5-m 
inute exposure. 
The observations were made as follows:— 
1. Leakage Test.—Put a charge on the inner cylinder; close 
the ends of large cylinder to exclude air currents; read time and 
deflection of leaves; let stand 15 or 20 minutes, and again read. 
2. Earth the inner cylinder; put on a +ve charge of from 
150 to 225 volts; let stand about a minute, read position of leaves 
on an even minute, and at once start rotating the fan. The fan 
is rotated at a rate of about 80 revolutions per minute. After 
five minutes’ uniform rotation, read the position of the leaves 
again; earth the inner cylinder, put on a negative charge, and 
repeat alternately with +“° and —”° charges. 
The computation of conductivity is carried out as indicated in 
table 1, and of electrical potential in table 2. 
CONDUCTIVITY OBSERVATIONS.—GERDIEN Apparatus No. 1. 











Station, Winter Harbour. Date, June 21, 1909. 
| | F | | = en 
Scale | | | 
Time | Sign | | Div. V . |Log V| Diff. |xx104 Remarks. 
Left | Right | 
h. m 
16 23) + 19.0 | 16.0 | 35.0 | f Leakage 
an AOL ARS RL nr ig Tete 
7 3 +. 470 | 16.0 | 32.0 | 238 988711. .. |Bar. 30.16 
8l .. | 13.0 | 11.2 | 24.2 | 177 | .248 0.119 1.90 Temp. 39 
13! 4) 16200) 718.0) | Seo Ore)’ Sameer .. |Hum. 94 
18} .. | 11.2) 9.6 | 20.8 | 152 | .182| 0.134] 2.14 [Wind calm 
93) 7 1.16 :0 | 14.0) 30,0.) 220.) aaah are .. (Sky blue 
og ., | 15.0 | 18.0 | 28:0:| 207) .316|-0.0801, 0.48 | 
39102 118.5 :| 15.60 8400 eh “SSR .. [Watch No. 54 
38 15.0 | 12.0 | 27.0 | 200 | .301) 0.081] 1.30 {fast 2h. 15m. on 
| | L.M.T. 
49, 15 | 12.6 | 27.6") 204) ane ie 
4s} .. |12.7 | 11.5 | 24.2 | 178 | .250! 0.060] 0.96 
BB). 2200) 16.011 14,5: | eb) a eee 



58; .. 9.0 | 10.0 | 19.0 |. 138 | .140! 0.184] 2.94 
| | 


