99 
When the cell was first put into circuit with the battery, 
the current began to increase, and gradually reached a maxi- 
mum. When the battery was cut out of circuit, a defiection 
due to polarisation could be obtained on altering the shunt 
of the galvanometer. This deflection diminished slowly and 
regularly to zero. 
4. Concentrated solution of CUSO4 with Cu plate elec- 
trodes. 
With this cell it was also found that a gradual increase 
set in on making the circuit. The current reached a 
maximum in about 8 minutes, and remained steady at its 
maximum. 
This cell also gave a weak but persistent polarisation 
current, which first began to increase, reached a maximum, 
and then decreased, taking over one hour with 200 ohms 
in circuit to reach its initial value. It was but slightly 
diminished at the end of several hours. 
€i.p. 
Numevical values of ^ e! 
From above experiments— 
1. Pt. foil in dilute H2SO4, 20 %, e = P69 Daniell. 
2. Pt. wire ,, ,, e = T92 ,, 
3. Zii plate in concentrated ZnS04, ’004 „ 
4. Cu „ ,, CUSO4, e- ’01 „ 
The last two values are not to be considered as absolute, 
but rather as showing the orders of magnitude of the two 
polarisations. 
Observations were made of the value of e under varying 
conditions of circuit. Thus if one of the three variables, 
current, EMF, and Resistance was kept constant, while the 
other two were varied, the following results were obtained:— 
1. C kept constant, E and R varied. 
E = 1 Daniell, R= 3,100 ohms, e- '9 Daniell. 
E = 2 „ R= 5,860 „ e = D6 
E = 3 „ R- 8,290 „ e=2-0 
E = 4 „ R=ll,040 „ e = 2-l 
E = 6 „ R-18,510 „ e = 2-l 
E = 8 R= 24,990 „ e = 2T 
3? 
3) 
