Report of the Keiv Observatory Committee. 



5 



the same time a new silk suspension was fitted to the needle of the 

 electrometer, and the instrument generally overhauled, and a new 

 scale determination was carried out. 



The records remained satisfactory until November, when the 

 battery potential again began to fall oft' rapidly. Between November 

 24 and 27 the whole sixty cells were cleaned and recharged with a 

 satisfactory result, and on the latter date one-third of the cells were 

 removed to contract the scale, in order to record high winter values, 

 as explained in last year's Report. 



On several occasions it had been noted that the electrometer needle 

 had a tendency to " set " when the acid in the interior jar had been in 

 use for some time. This i; setting " largely interfered with the freedom 

 of the needle. It has, however, been considerably reduced, by substi- 

 tuting a single platinum wire connection for the double gridiron 

 form hitherto employed. 



In May another portable electrometer, No. 80, was purchased from 

 White, of Glasgow-; it is furnished with some additions to the usual 

 pattern, which experience at the Observatory suggested as likely to 

 prove beneficial in reducing induction effects. This electrometer 

 has been used since, with the older instrument, White, No. 53, 

 in obtaining the scale value of the self-recording instruments, de- 

 terminations being made on February 7, April 1, May 26, June 16, 

 September 6, and November 28. 



Inspections. — In compliance with the request of the Meteorological 

 Council, the following Observatories and Anemograph Stations have 

 been visited and inspected : — Stonyhurst, Yarmouth, North Shields, 

 Alnwick Castle, Fort William, Glasgow, Aberdeen, and Deerness 

 (Orkney), by Mr. Baker; and Radcliife Observatory (Oxford), Holy- 

 head, Fleetwood, Armagh, Dublin, Valencia, Falmouth, and St. 

 Mary's (Scilly Isles), by Mr. Constable. 



III. SE1SMO LOGICAL OBSERVATIONS. 



The seismograph referred to in last year's Report was delivered 

 by Mr. R. Munro in March. It is of Professor J. Milne's " unfelt 

 tremor" pattern, the motion recorded being that of a horizontal 

 pendulum or boom with along period of vibration (fifteen to eighteen 

 seconds from rest to rest). It is intended to measure tbe tilting of 

 the ground along an east- west line, the boom itself lying due north 

 and south. 



At the suggestion of Professor Milne, who visited the Observa- 

 tory, the site selected for at least a temporary trial is in the base- 

 ment, inside the double-walled wooden room, originally designed for 

 pendulum observations, and sometimes used as a warm chamber for 

 chronometers. At first difficulties were encountered from wandering 



