1865.] President's Address. 491 



nishing progressively from 1859 to 1863-1864: in 1863 and 1864 the 

 amount of disturbance was nearly identical, and was only about one-third 

 of the amount in 1859. From the general aspect of the photographic 

 traces in the present year (1865), there appears reason to believe that 

 the epoch of minimum is now passed. If this be so, the years 1863-64 

 will have been the fourth return of the epoch of minimum since 1823-24 

 (Arago's Meteorological Observations, English translation, Editor's Note, 

 pages 355 to 357)> thus confirming the coincidence with the decennial 

 variation of the sun-spots discovered by Schwabe. 



Those who regard with interest the progressive establishment of the 

 theory which assigns a cosmical origin to the Terrestrial Magnetic Varia- 

 tions, will have noticed the remarkable, but not altogether unanticipated, 

 testimony borne to the decennial variation by the annual values of the 

 magnetic Inclination at Toronto in the years from 1853 to 1864, in the 

 volume recently published by Mr. Kingston, Superintendent of that Ob- 

 servatory. The general effect of the disturbances of the Inclination at 

 Toronto is to increase what would otherwise be the amount of that ele- 

 ment ; therefore, if the disturbances have a decennial period, the absolute 

 values of the Inclination (if observed with sufficient delicacy) ought to 

 show in their annual means a corresponding decennial variation, of which 

 the minimum should coincide with the year of minimum disturbance, and 

 the maximum with the year of maximum disturbance. I have placed in a 

 note (C)* the annual values derived in each case from the regular monthly 

 determinations, commencing with 1853, and ending with 1864, taken 

 from the publication referred to, whereby it will be seen that an actual 

 variation does exist such as I have indicated, 1853 being a minimum and 

 1859 a maximum ; the increasing progression being uninterrupted from 

 1853 to 1859, and the decreasing progression uninterrupted from 1859 

 to 1864, the date of the latest published results. 



It was in the year 1853 that the Toronto Observatoiy was transferred 

 to the provincial authorities, and was placed by them under the direction 

 of Mr. Kingston. The Inclinometer employed is the same which was 

 described in a paper in the Philosophical Transactions for 1850, Art. IX., 

 entitled "On the Means adopted in the British Colonial Magnetic Ob- 

 servatories for determining the Absolute Values, Secular Changes, and 

 Annual Variations of the Terrestrial Magnetic Elements ;" and the as- 

 sistants by whom the observations were made were the same persons who 

 had performed the same duties when the Observatory was under, the 

 direction of Officers of the Artillery. The results are a r valuable exemplifi- 

 cation of the accuracy attainable when proper attention is paid to the 

 selection of the instruments, and to the employment of careful and skilful 

 observers. Such evidence is of more than ordinary interest at the present 

 time, when such institutions are rapidly increasing. 



We have recently learned by a despatch from Sir II. Barkly, Governor of 

 * See note C, p. 513. 



VOL. XIV. 2 P 



