ASTRONOMY.
91
greater movements will show an excess, the slower ones a defect, ac-cording to phoronomical principles. Nevertheless, there are somereasons which make me incline to the opinion, that the general direc-tion of the movement is towards the west. Farther on, I shall returnto this question ; but in this place, the following observation maybe made, namely, that a new spot bursts out almost always to theeast of an older one, very seldom to the west. Since it is of someinterest, the linear velocity has been computed for some of the spotswhich seemed imbued with a somewhat considerable motion (as onthe annexed Table C). Here are velocities up to between 300 and400 miles the hour, which is not so extraordinary, considering that thesun’s diameter is 112 times that of the earth, and that the strongesthurricanes on the earth are supposed to possess a velocity of 120miles an hour. For the sake of comparison, it may be mentionedthat the velocity of rotation of a point at the sun’s equator is betweenfour and five times as great as of a point at the earth’s equator; or asthe latter is nearly 900 miles, the former is about 4,000 miles, the hour.
TABLE C.
Some of the greater Absolute Velocities per hour of Solar Spots observed in Geographical
Miles.
Spot.
Velocity.
Spot.
Velocity.
No. 12
20
Wo. 273
109
232
29
144
129
215
43
230
129
202
57
17
132
22
62
82
153
118
63
286
168
132
73
95
169
53
75
113
207
242
84
35
222
19
92
88
238
204
98
90
261
81
102
67
277
66
106
219
366
The second fact which I wish to draw attention to, results by com-bining together the heliographic positions of different spots, and maybe pronounced, for the present, in the following thesis : —
In certain localities of the solar surface , the spots arise more fre-quently than in others.
A glance upon the map shows immediately that the spots are ar-ranged in two girdles or belts, one to each side of the equator.