429 
of Edinhiirgh, Session 1883 - 84 . 
ing by the brush did not alter the mean very much. The value 
obtained, 42, does not differ much from the final mean, 45. This 
result gives strong support to the explanation given in this paper 
of the occasional positive electricity produced in zinc and some 
other metals. 
Table III . — Observations of 2^tli December. 
First Series. — After being rubbed with warmed chamois leather. 
Copper (disc). 
Gold. 
Copper (el. -pL). 
Silver. 
ISTickel. 
105 
128 
60 
70 
48 
105 
130 
70 
68 
44 
105 
145 
80 
75 
48 
128 
180 
75 
80 
45 
138 
170 
70 
85 
44 
Mean 116 
151 
71 
76 
46 
Whisked. 
Whisked. 
Whisked. 
145 
230 
110 
120 
78 
165 
200 
117 
105 
87 
157 
225 
100 
110 
75 
140 
200 
105 
115 
73 
175 
228 
105 
115 
80 
Mean 156 
216 
107 
113 
79 
Second Series . — After being cleaned again. 
Copper (disc), 
Copper (el.-ph), 
Tin, 
Antimony 
1 with emery 
with warm 
with emery 
and flannel. 
flannel. 
and flannel. 
by hand. 
76 
80 
210 
65 
103 
90 
190 
60 
130 
83 
188 
78 
130 
88 
190 
80 
145 
100 
200 
78 
Mean 117 
88 
196 
72 
Whisked. 
Whisked. 
Whisked. 
200 
105 
210 
180 
108 
170 
Aluminium, 
200 
115 
200 
chamois leather 
190 
104 
and hand. 
150 
103 
Mean 193 
95 
Mean 184 
107 
Reverse Side. 
73 
240 
78 
315 
84 
240 
90 
1 
Mean 265 
Mean 84 
