Report of the Kew Committee. 



83 



Mectrograph. — This instrument has been in continuous action 

 through the year, with the exception of a few occasions during the 

 severe frost of last winter. 



In July the instrument was dismounted, and a fresh supply of acid 

 placed in the jar, the charge-keeping properties of which had become 

 slightly deteriorated. 



The tabulation of the curves given by this instrument has at last 

 been commenced, and a suitable glass scale, arranged on a plan 

 devised by Mr. Whipple, having been constructed by Mr. Baker, the 

 average hourly tension of atmospheric electricity at the collector of 

 the Electrograph has been determined for every hour in 1880, except 

 in those cases where registration failed either from disturbance or 

 instrumental defect. 



From these values the daily, monthly, and annual means have been 

 deduced, together with other facts bearing on the relations existing 

 between atmospheric electricity and different meteorological phe- 

 nomena. Some results of this investigation were by permission of 

 the Meteorological Council submitted by the Superintendent to the 

 Meeting of the British Association at York, in a paper which has 

 since been ordered by the General Committee to be printed in extenso 

 among their Reports. The expense of the tabulation was defrayed by 

 a special grant from the Meteorological Council. 



III. Solar Observations. 



The only solar work done at Kew during the past year has been the 

 regular maintenance of the eye observations of the sun, after the 

 method of Hofrath Schwabe, as described in the Report for 1872. 

 These have been made on 187 days, in order to preserve the continuity 

 of the Kew records of sun-spots. The sun's surface was observed to 

 be free from spots on three of those days. 



A small portable 2^ in. refracting telescope, with a magnifying 

 power of 42 diameters, is used by the observer. 



Transit Observations. — Ninety-four observations have been made of 

 sun-transits, for the purpose of obtaining correct local time at the 

 Observatory : 126 clock and chronometer comparisons have also been 

 made. 



In addition to these a considerable number of star transits have 

 been observed in connexion with the pendulum operations in progress 

 during the autumn of 1881. 



IV. Experimental Work. 



Winstanley's Recording Radiograph. — This instrument, designed for 

 the purpose of registering continuously the amount of radiation from 

 the sky, by mechanical means, upon a sheet of blackened paper, still 



G 2 



