1870.] 



President's Address. 



115 



It may be in the recollection of some of the Fellows that, in the Anni- 

 versary Address delivered in 1863, 1 ventured to suggest the interest and 

 probable value of a series of Pendulum Experiments at the principal stations 

 of the Great Indian Arc. Encouraged by the warm concurrence in opinion 

 and promised support of Colonel Walker, Superintendent of the Indian 

 Trigonometrical Survey, a circular note was addressed by myself, with the 

 concurrence of the Council, to several of the Fellows of the Royal Society 

 conversant with the subject; and the correspondence, including an outline 

 of the proceedings which in Colonel Walker's judgment would be required 

 in India, should the experiments receive the sanction of the Indian autho- 

 rities, was submitted through the proper channels to the Secretary of State 

 for India, and received the sanction of the Indian Government. 



The pendulums and accompanying apparatus having been prepared at 

 the observatory of the British Association at Kew (aided by a special 

 subsidy from the Government-Grant Fund placed annually at the disposal 

 of the Royal Society), were embarked for India, in March 1865, under the 

 charge of Captain Basevi of the Royal Engineers, appointed to conduct 

 the experiments with them in India. These have been executed in great 

 part, and are still in progress, under that officer's superintendence. In the 

 meantime the Royal Society has been favoured by a recent communication 

 from the Secretary of State for India, enclosing Col. Walker's official report 

 of wbat has been accomplished, and of what remains to be accomplished in 

 India, to complete the original programme — and transmitting a despatch 

 signed by the Governor General and other high authorities of the Indian Go- 

 vernment, requesting that the President and Council of the Royal Society 

 may be invited to suggest at an early day any supplementary measures 

 which they may deem desirable. 



It appears that, at the date of Colonel Walker's report, pendulum ex- 

 periments had been completed at twenty-five stations on the mainland of 

 India, extending from Cape Comorin in lat. 8° 5' N. to Mussoorie in lat. 

 30° 28' N., and at a 26th station, on the Island of Minicoy, midway between 

 the Maldives and the Laccadives, in lat. 8° 6' — and that five additional 

 stations had been allotted as the work of the present year, four of which 

 are in the high tablelands of India between 32° and 36° N., and one near 

 the mouth of the Indus. 



I had the pleasure of receiving, about the same time, a letter from 

 Colonel Walker himself, announcing his intention of being in England, on 

 furlough, towards the end of December, when he might be personally 

 informed of any further uses to be made of the pendulums in India — pro- 

 posing also that, on the return voyage to England, Captain Basevi should 

 be instructed to obtain the rates of the pendulums at Aden (suggested as 

 desirable, from its geographical peculiarities, by our Foreign Secretary, in 

 a letter to myself, printed in the Minutes of Council of June 1864), and 

 at a station to be selected in the vicinity of the Bitter Lakes. Colonel 

 Walker also suggested that, on the arrival of the pendulums in England, 



