ATMOSPHERIC
775
ELECTRICITY
Table I. Mean Diurnal Inequality for the Year. Station. Period. Days. h 1 Hour. 1 2 3 4 5 6 7 8 9 10 11 Noon. 1 2 3 4 5 6 7 8 9 10 11 12 Mean value in volts.
Cape Thorsden. 1882-83. Quiet. 3-33 1-87
Sodankyla.
Kew Observatory.
1882-83. All. 3-0 2-5
1880.
3-5 1-0
1880. All. 3-3 1-4
3-3 1-4
All. 3-0 1-8
97 99 94 89 93 96 94 102 98 93 98 96 99 99 101 105 105 109 108 114 110 100 101 99
91 85 82 84 89 91 97 100 98 102 98 102 105 107 108 108 108 110 102 111 111 104 108 93
87 79 74 72 71 77 92 106 107 100 90 92 90 91 92 98 108 121 134 139 138 128 113 99
102 95 88 85 85 88 97 97 102 90 94 91 90 88 85 88 99 110 118 129 130 130 114 105
101 95 86 84 84 88 95 95 101 91 96 95 94 89 85 90 97 108 121 127 132 127 114 105
97 89 87 86 86 92 100 102 100 101 96 97 96 94 95 97 102 108 111 115 117 117 111 104
10
65
51
87
91
Greenwich.
Florence. Perpignan. Lisbon. 1886-88.
1883-85. All.
92 83 77 75 74 82 100 112 113 107 100 95 92 90 89 89 94 113 121 129 132 127 114 100
Cape Horn. 1887-90. 1890-95. 1882-83. Pos. Dry. Dry. 3-5 7-8 2-0 Batavia.
8-4 1-5
All. 3-0 0-5
7872 71 72 77 92 107 114 111 100 96 99 99 97 99 105 113 126 131 129 120 109 97 86
84 80 78 81 83 92 101 105 104 104 102 108 111 114 109 108 108 111 116 114 109 102 92 85
147 141 135 128 127 137 158 104 67 42 35 30 30 30 33 41 67 91 120 137 146 148 151 147
125 114 109 102 101 117 147 119 82 55 46 43 42 43 46 53 73 108 145 155 155 147 143 130
82 73 85 81 85 95 106 118 119 123 123 115 112 94 89 88 84 110 107 123 112 99 85 98
99
79
967
100
119
Table II. Diurnal Inequalities. Station. Cape Thorsden. Period.
Hour. 1 2 3 4 5 6 7 8 9 10 11 Noon. 1 2 3 4 5 6 7 8 9 10 11 12
Sodankyla. Summer.
90 79 78 74 74 80 86 95 91 106 98 98 116 113 121 111 105 115 118 117 115 112 113 95
99 84 90 99 111 114 117 122 109 101 97 100 97 97 93 96 106 92 102 106 90 90 103 85
97 111 118 103 103 114 108 107 92 89 97 98 101 96 93 92 101 98 103 102 95 86 90 102
87 83 80 76 78 78 82 98 102 102 101 100 104 104 110 119 112 116 124 126 126 98 103 89
Winter.
Summer.
Winter.
Summer.
Winter.
Summer.
87 84 76 77 78 82 94 97 98 102 103 107 107 109 111 116 112 114 117 113 111 110 102 93
110 101 98 96 94 101 107 111 102 98 86 94 85 82 78 81 93 98 99 108 118 124 120 116
68 67 62 63 68 83 102 122 125 112 100 106 106 106 106 111 117 126 131 126 117 104 93 80
88 80 77 81 94 112 118 111 109 101 102 105 98 90 88 89 93 103 111 115 119 115 106 95
76 74 75 79 77 82 93 100 106 109 108 11.3 117 116 114 115 116 120 128 115 105 98 86 75
93 86 82 81 86 96 108 105 100 97 96 98 107 114 104 102 101 104 106 116 115 110 97 95
145 139 137 131 132 138 166 118 74 43 35 31 29 28 24 30 60 88 119 138 145 148 149 148
Greenwich.
Perpignan.
Lisbon.
1880.
1894 and 1896.
1888.
1885-86.
1882-83. Jan. to May to WinApril. Aug. ter.
Batavia. (7‘8 metres.) (2 metres.) 1890-95. 1887-90. Win- Sum- Win- Sumter. mer. ter. mer.
Kew Observatory.
Winter. Summer, 94 92 84 81 80 83 91 94 106 100 97 100 99 94 90 97 104 114 124 129 128 120 106 97
115 104 92 90 95 97 105 100 91 (71)? 93 85 85 78 75 74 85 96 111 125 144 144 130 121
results for the Bureau Central Meteorologique, the Eiffel Tower, and the College de France, Paris, the last based on diagrams in a paper by Chauveau (Seances de la Soc. Franc, de Physique for 1899, p. 91). In this paper Chauveau suggests that there are at ordinary stations two distinct types of diurnal variation, viz., a summer type
149 142 135 127 123 136 153 92 64 40 36 30 33 32 41 49 74 94 122 135 147 148 152 146
124 114 109 100 102 115 152 131 91 57 47 42 40 40 43 50 73 108 144 153 152 145 140 126
127 114 108 103 100 118 142 93 76 54 46 44 42 46 50 55 73 107 146 156 157 150 145 133
possessed of two distinct maxima and two distinct minima, and a winter type showing only one maximum (in the evening) and one minimum (in the morning), or else closely approaching this as an ideal. Arguing from the results on the Eiffel Tower and from those on a high staging at Trappes, Chauveau draws the conclusion that the afternoon
