Report of the Kew Committee. 79 



Grand, application was made to H.M. Commissioners of Woods and 

 Forests for permission to erect a telegraph line from the Observatory 

 to the London and South "Western Railway skirting the Old Deer 

 Park. This was granted, and a line has been set up placing the 

 Observatory in direct electrical communication with the Chief Post 

 Office in Richmond. 



A relay and chronograph have been purchased and placed in the 

 circuit, and every morning, excepting Sundays and holidays, the 

 10 A.M. signal from the Royal Observatory, Greenwich, is recorded 

 beside the beats of the Observatory Standard Clock (French) on the 

 same tape. The signals have been observed daily by means of the 

 galvanometer for the past two months, but the chronograph was only 

 regularly set to work on the 31st October, delay having arisen on 

 account of the necessity of protecting the apparatus against lightning. 

 The cost of the chronograph and attachments to the Standard 

 Clock has been defrayed by a grant from the Royal Society. 



Pendulum Experiments. The swinging of the Indian Invariable 

 Pendulums at the Observatory has been delayed by the operations 

 attendant on the establishment of the time signal connexion with the 

 General Post Office, and also by failure, up to the present, of informa- 

 tion from the American officers as to certain details of their practice 

 when observing with the apparatus in America and elsewhere. 



Meanwhile experiments have been made to determine the vacuum 

 correction of the two thermometers, Nos. K.S. 667 and 668, used on 

 the dummy to replace those broken in travelling. It was observed 

 that a reduction of 27 inches in the barometric pressure lowered 

 their zero points by 0'25. Other observations were also made to find 

 the relative degree of accordance during changes of temperature 

 between the indications of the thermometers in the interior of the 

 vacuum- chamber and that attached to the Richard thermograph 

 placed in close proximity to its outer surface. 



During these trials the holding capacity of the chamber has been 

 thoroughly tested and found to stand low pressures extremely well. 



Constants of Hobinson Anemometers. By permission of the Com- 

 mittee, Mr. Whipple has attended at Hersham on several occasions, and 

 assisted Mr. W. Dines, B.A., F.R. Met. Soc., in the experiments in 

 progress, on behalf of the Wind Force Committee of the Royal Meteoro- 

 logical Society, for determining the value of the Robinson constant for 

 anemometers of various dimensions, and also for verifying the factor 

 for converting wind velocity into pressure. 



The experiments are similar to those carried out at the Crystal 

 Palace in 1874, and described in the Report for that year. 



A Preliminary Report on the experiments was read before the 

 R. Met. Soc. meeting in May, 1888, and is printed in the ' Quarterly 

 Journal,' vol. 14, p. 253. The results compare very favourably with 



