History of the Kew Observatory. 



69 



the project were received from all those whose instruments were work- 

 ing under satisfactory circumstances. 



An examination of the records for the year 1879 indicated the 

 month of March as that most suitable for the purpose of the com- 

 parison. Accordingly, a further request for copies of the Declination 

 carves for that month was issued, and, in response, they were received 

 from Coimbra, Colaba, Lisbon, Mauritius, Melbourne, St. Petersburg, 

 Stonyhurst, Toronto, Utrecht, Vienna, and Zi-Ka-Wei. 



The comparison of these magnetic curves was undertaken by Pro- 

 fessor W. Grylls Adams, who communicated to the Swansea Meeting 

 of the British Association a preliminary account of the principal facts 

 which came to light. This was followed by a second paper printed in 

 the .Report of the York Meeting, 1881. 



At the request of the Council of the Royal Astronomical Society, the 

 valuable collection of MSS. containing the memorable series of sun-spot 

 observations made by Hofrath Schwabe, of Dessau, during the years 

 1825 to 1867, which had been deposited in the Library of the Obser- 

 vatory, the first volumes since 1865, was transferred to the Society's 

 Library at Burlington House, London. In order, however, to render 

 the collection of sun-spot observations as complete as possible, and to 

 prevent the total loss of the observations in case of fire, the Committee 

 voted the sum of 90Z. to defray the cost of making a complete copy of 

 the solar drawings. 



This was accordingly done, and accurate tracings made of every one 

 of Schwabe's drawings. These were pasted into blank books, and any 

 im.porta.nt notes were transcribed at the same time. 



The Observatory, therefore, now possesses a complete record of the 

 condition of the sun's surface, extending from November, 1825, to the 

 present date. 



In 1881, an application was received from Major Herschel^ R.E , 

 F.R.S., by authority of the India Office, for permission to make certain 

 experiments with the invariable pendulums deposited at Kew, and for 

 the loan of the instruments, with their accompanying appliances, with 

 facilities for prosecuting the experiments at the Observatory. 



These requests were granted, and in the autumn of the year operations 

 were carried on, both in the Pendulum Room and in the Experimental 

 House at Kew. 



On completing his work Major Herschel conveyed the instruments 

 he employed, first to the Royal Observatory, Greenwich, and sub- 

 sequently to a house near Portland Place, London. Series of observa- 

 tions were made in both those places, with the object of reducing to a 

 common standard the determinations of gravity made by Kater, Airy, 

 Sabine, and others. 



On the conclusion of these latter experiments, Major Herschel con- 

 veyed the pendulums, clock, &c, to America, where, after making a 



