110 



PROCEEDINGS OF THE CANADIAN INSTITUTE. 



are often noted by a jerk in the regularity of the trace, and this appears to be 

 observable at every station. Returning from this aside, I will ask you to examine 

 the magnetic tracing for the year 1859. You will see that Carrington and 

 Hodgson's disturbance was fairly severe on April 21st, May 19th and June 16th, 

 strong on July 11th, slight on August 8th, and very severe on September 2nd. These 

 various dates are separated by about the interval of a solar rotation, and I have 

 arranged the other curves so that the same solar meridian which faced the earth on 

 that September 1st, also faced it at the dates placed underneath it in all, adopting my 

 own rate of solar rotation. It differs from the one adopted at Greenwich by 3/100 



1SE?. 



APK17I882 ' 



70CT. 



No. 1, 1859 [| 



No. 2, 1869 



No. 3, 1872 



No. 4, 1872 

 No. 1 5, 



No. 6, 1882 



No. 7, 1886 



No. 8, 1886 



No. 9, 1892 



No. 10, 1893 



No. 11, 1893 



No. 12, 1898 



No. 13, 1901 



of a day only, but in the forty years covered by these curves that equals twelve 

 days or nearly half a solar rotation. With the uncertainty above referred to as 

 prevailing in reference to this exact period I need scarcely say that we should not 

 yet be too positive of correctness. The concordances apparently established by 

 my diagram and table may be accidental. The diagram is made to show that 

 great spots are associated with magnetic storms, and each of the curves gives 

 some noteworthy proof of this fact ; their being placed under each other has an 

 independent bearing upon the other fact as well. I have taken all the great spots 

 of which I have found an account in the volumes accessible to me. 



EOT'S. 



135 



174 

 176 



311 



354 

 357 



435 



455 



458 



523 



