512 Anniversary Meeting. [Nov. 30, 



transmitted to Melbourne, the authorities there were at first disposed to 

 embrace it ; but subsequently, on further consideration and correspondence, 

 they determined to revert to the original plan, of a telescope to be con- 

 structed by Mr. Grubb expressly to meet in the most perfect attainable 

 manner all the special requirements of the case. This plan is described in 

 a letter addressed to Dr. Robinson on the 3rd of December, 1862, being the 

 thirteenth letter in the printed Correspondence referred to. It seems scarcely 

 possible to doubt the wisdom, in every point of view, of the decision thus 

 arrived at. The alterations which would have been required in Mr. Lassell's 

 telescope would have demanded a large proportion of the time and the ex- 

 pense needed for the construction of the new one ; and the result would have 

 been that Europe would have lost all the services which Mr. Lassell's tele- 

 scope may still perform while Australia would have had a much less per- 

 fect instrument, for the especial purposes in view, than it will now possess. 

 In April 1864 a proposition for a grant of ^65000, to cover the expense 

 of constructing a telescope, was submitted to the Colonial Legislature by 

 one of its members, Mr. Alexander John Smith, also a Member of the 

 Board of Visitors of the Observatory, who, previously to his residence in 

 Victoria, had been one of that band of highly-trained naval observers who, 

 under the command of Sir J. C. Ross, had accomplished, between the 

 years 1839 and 1843, the Magnetic Survey of the Antarctic regions, and 

 had subsequently become one of the officers employed with Capt. Kay in 

 the Magnetical and Meteorological Observatory at Hobarton. This pro- 

 position was successful ; and the notification received from Professor Wilson 

 is printed in the text of this Address, p. 483. 



NOTE B. 



The number of hourly tabulations from the photographic traces of 

 the bifilar magnetometer at Kew, between January 1, 1858, and December 

 31, 1864, is 60,491 : of these, the number in which the amount of dis- 

 turbance from the normal of the same year, month, and hour equalled or 

 exceeded 0*150 division of the scale, or -0015 of the total horizontal 

 force at Kew, was 5932, being about one in ten of the whole number of 

 tabulated hourly values. The aggregate value of the 5932 disturbed ob- 

 servations in parts of the bifilar scale, of which 1 inch equals "01 of the 

 whole horizontal force, was as follows : 



Year ending December 31, 1858 267*893 inches. 



1859 369-286 



1860 270-349 



1861 206-748 



1862 183-645 



1863 114-642 



1864 114-725 



The mean annual value in the seven years is 218*184 inches ; and the 

 ratios of disturbance, in each of the seven years, to the mean annual value 

 are as follows : 



