31(5 DR. C. CHREE: ATMOSPHERIC ELECTRIC POTENTIAL RESULTS AT IvEW 
distinctly improves the agreement with observation. I have expressed Chauveau’s 
values for the amplitudes in terms of the corresponding mean values of P taken as 
unity, and have calculated corresponding results for Kevv from Everett’s data as well 
as my own. In the latter case the values assigned to “ summer ” and “winter” are 
derived from the seasonal data at the foot of Table V., making use of the mean values 
of P given in Table I. For September and October I have taken the arithmetic 
means of the c’s and as for the two months. It seemed hardly worth while analysing 
a mean diurnal inequality from the two months combined, though that would have 
been more strictly correct. In the case of Everett’s data the values refer in each 
case to a mean diurnal inequality for the period stated. Table VIII. gives the values 
thus found for the amplitudes, and Table IX. applies similarly to the phase angles. 
In this table the Kew angles have been modified so as to answer to local solar time, 
so as to be strictly parallel to Chauveau’s angles. 
Table VIII.—Diurnal Inequality. Comparison of Amplitudes. 
Winter. 
September and October. 
Summer. 
C l. 
c 2 . 
Cs- 
r 4 . 
Cl. 
c 2 . 
c 3 - 
r 4 . 
Cj. 
C-2. 
^3* 
c 4 . 
Kew, 1862-4 
Kew, 1898-1 
1904 / 
Bureau Cen-1 
0-283 
0-160 
— 
0-284 
0-207 
— 
— 
0-127 
0-229 
— 
— 
0-102 
0-103 
0-033 
o-oio 
0-060 
0-190 
0-033 
0-025 
0-079 
0-213 
0-021 
0-027 
tral, 1893 J 
Bureau Cen -1 
0-223 
0-203 
0-072 
0-084 
tral, l 
1894-8 J 
Eiffel "tower, 1 
0-220 
0-104 
0-035 
0-031 
0-144 
0-211 
0-060 
0-055 
0-130 
0-200 
0-040 
0-068 
1893 J 
Eiffel Tower, 1 
0-036 
“ 
0-188 
0-044 
0-003 
0-0.28 
1896-8 J 
0-157 
0-007 
0-015 
0-133 
0-085 
0-023 
0-021 
Table IX.—Diurnal Inequality. Comparison of Phase Angles. 
Winter. 
September and October. 
Summer. 
; a 4 . 
a 9. 
- 
«3- 
cc 4 . 
« 1 . | CL 2 . CC 3 . 
a 4 . 
an 
a 2 . 
a 3 . 
a 4 . 
o 
o 
O 
o 
000 
0 
0 
0 
0 , 
Kew, 1862-4 . 184 
193 
— 
— 
170 189 — 
111 
179 
„ 1898-1904 . . . . ; 206 
180 
23 
239 
171 198 11 
301 
87 
186 
116 
304 
Bureau Central, 1893 . . 
96 
200 
190 
8 
„ 1894-8 . 223 
206 
45 
0 
182 213 358 
11 
95 
197 
157 
352 
Eiffel Tower, 1893 . . . — 
— 
— 
_ _ _ 
— 
196 
207 
114 
25 
„ 1896-8 . . j — 
212 185 122 
331 
216 
171 
79 
330 
