ON THE KEW OBSERVATORY. 369 



On the same day and subsequently, a few experiments were commenced 

 on M. Claudet's actinometer. 



On January 20, 1851, Mr. Phipps (of the Woods and Forests) examined 

 the building; when its state, as to dry rot, &c., was represented, and an in- 

 timation was made that probably Lord Seymour would visit it. 



On the 25th, Professor Potter's "Aerometric Balance for measuring the 

 density of the air in which it is situated," arrived for examination and expe- 

 riment, but was required to be returned before any results which could be 

 confided in were obtained. The difficulties of observing the instrument 

 under unobjectionable conditions seemed almost insurmountable. It is de- 

 scribed in the Philosophical Magazine, vol. xxxvii, p. 81. 



On May 8, Lieut. Fergusson, of the Indian Navy, began a little course 

 of study and manipulation relative to all our methods of procedure in the 

 self-registering system, and in eye observations of atmospheric electricity, &c. 

 It was continued daily during about two weeks, at the end of which time he 

 had become well qualified to prosecute and conduct such operations and ob- 

 servations. 



At the end of May, Mr. A. Broun, late Director of Sir Thomas Brisbane's 

 magnetic observatory, appointed to the Trevandrum observatory, commenced 

 a similar course, which lasted (at intervals) about 2 weeks, and terminated 

 with like success*. 



On June 20, Colonel Sabine and Professor Stokes decided upon using the 

 South Lower Hall for the prosecution of Professor Stokes's proposed ex- 

 periments to determine the index of friction in different gases. 



On the 24th, Mr. Weld, Assistant Secretary of the Royal Society, visited 

 the Observatory, and informed me that he was directed to send a large 

 quantity of apparatus belonging to the Royal Society to be deposited here. 

 He examined the localities in which they could be properly lodged, viz. 

 the glass cases, &c., formerly occupied by His Majesty George the Third's 

 splendid collection of instruments of a similar kind; and on the 26th, many 

 cases containing the Royal Society instruments arrived ; but the operation 

 of unpacking, &c. was deferred to an early day after this meeting of the 

 British Association. 



Some boxes (probably containing papers) locked and without keys, arrived 

 with the instruments and were not opened. 



Between this time and the end of the month all outstanding bills due by the 

 establishment were paid, excepting three or four very small accounts (which 

 presented a little difficulty in adjustment, &c.) ; and a tabulated statement 

 embracing the whole expenditui-e and receipts for the (British Association) 

 year was delivered to the Kew Committee, by which account it appears that 

 the total sum expended on the Establishment account has been £309 2s. 2d. 

 (including the above-m . ntioned small accounts), which sum is £29 135. less 

 than the amount of the grant made at the Edinburgh meeting on August 1, 

 1850, added to the residue of the former grant made (in 1849)t. 



In the course of the year numerous meetings of the Kew Committee, and 

 very many individual attendances of its President, Colonel Sykes, Colonel 

 Sabine, and Mr. Gassiot, have taken place at the Observatory, 



Our visitors have been numerous, and almost exclusively gentlemen of high 

 scientific reputation. 



* An electrical apparatus of the kind described at p. 339, ante, has since been put into 

 course of construction for Mr. Broun. 



t The sum annually expended has always been somewhat less than the ^ant and residue ; 

 sometimes considerably less. 

 1851. 2n 



