112 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



" our latitude? " The converse, as he puts it, that there are magnetic storms not 

 accompanied by spots, proves little — the cause of the storm may have been in a 

 solar region where spots do not appear, or, for reasons we cannot think of, may 

 not have given rise to spot phenomena. 



Several astronomers still cling to the idea that to prove the connection a spot 

 must be absolutely central at the time of a magnetic storm. The diagram just 

 explained shows that the spot ofcen lags a day or two behind its related storm. 

 It also indicates that there are three active meridians on the sun. I am not yet 

 prepared to speak of the latitude of active spot regions, but I have checked the 

 prominences for several years, and while they too are apparently more numerous 

 on three meridians, they are strangely distributed in belts, like those of Jupiter 

 and Saturn, while there seem to be extensive regions of comparative quietude. I 

 find that Professor Wolfer, of Zurich, has been doing similar work, and his results, 

 which I have seen in the Memorie of the Society of Italian Spectroscopist=i, are 

 apparently the same as my own.* As I have worked out each year separately, the 

 question of the exact rate of rotation is not seriously involved. I do not at 

 present attach a high value to this work, but it is interesting as showing changes 

 in the latitude of prominence belts. Some years this activity extends to near the 

 poles, and we have a belt of prominences in latitude 80°. The next year it may 

 be five degrees or even more nearer to the equator. Sometimes prominences are 

 numerous in the northern solar hemisphere, and again the southern hemisphere 

 may exhibit more activity. Prominences often occur in the neighborhood of spots, 

 but frequently where none are visible, and the range of prominences is much 

 greater than that of spots, for they have been seen at the very pole. I have not 

 been able to discover that they aftect the needle in any way, though they are more 

 frequent and larger when sun-spots are many and magoetic disturbance great. 



I must not conclude without a notice of the labours of Dan Carlos Honore, 

 director of the International Solar Institute of Montevideo. Like myself he found 

 it needful to arrive at a true period of solar rotation but he pursued the 

 meteorological method. Professor Frank H. Bigelow, of Washington, D.C., 

 had already shown similarities between magnetic curves and North American 

 temperature waves, and by making a time allowance for the movement of pulses of 

 heat and cold from the Rocky Mountains towards the Atlantic Coast, he brought 

 them into tolerable harmony. Mr. Honore does not attack this concordance ; he 

 takes as a guide the normal temperature of each day, attributing the surplus or 

 defect of heat to radiations from the sun. The days of surplus heat are shown in 

 his figures on one side of a circle and the days of exces^ of cold on the other, he 

 then finds a marked periodicity, and declares the synodical solar rotation to be 

 27,241,326 days. I understand he thinks the solar shell from which we get the 

 most effective heat rotates in that time, and if the shell which causes electrical 

 manifestations rotates a little more slowly, according to my reckoning, there is 

 nothing contradictory in that difference. Mr. Honore has so much confidence in 

 his theory that some parts of the sun are hypothermic, and cause an excess of heat 

 when turned towards the earth, that he has prepared tables of solar rotation 

 covering hundreds of years. On dividing the year into two, and superimposing 

 the curves, he found an inequality, and concluded that there is an interior sun, 

 with an axis slightly inclined to that of the photosphere, and a rotation slower by 

 0.00867 of a day, which leaves 363.33 days for the heliothermic year and 27.25 

 days exactly for the synodical rotation of the interior sun. With these data Mr. 

 Honore thinks he can define the latitude as well as the longitude of the solar 

 regions on this interior sun which send us heat, and even by those whose 

 radiations he believes cause earthquakes. He has sent me diagrams of solar 

 thermic centres, calculated by his tables, also other diagrams which localise the 

 solar seismic centre, which he thinks controls the Mexican volcanic field in a 

 seismic circle of 15 heliothermic years, or 200 synodical rotations of the interior 

 sun. With this cycle he identifies every one of the long list of Mexican earth- 

 quakes published by the Antonio Alzate Society. I have the calculations, not yet 

 carefully examined. 



I think the sun's condition does influence the earth in the matter of cold and 

 hot days, but the number and area of sun spots has but a slight connection with 



* Vol. XXIX, dispensa 7a. 



