Report of the Kew Committee. 



215 



Readings were continuously made from January 1 to July last, and 

 are now under discussion. 



Turf has been laid down under the screen of the thermograph, with 

 a view to avoiding effects of radiation as much as possible. 



The use of meteorological self-recording instruments having been 

 partially discontinued, at Armagh, Mr. Whipple dismounted and 

 packed the barograph and thermograph, and they have been returned 

 for storage to the Observatory. 



Electrograpli. — The new quadrant electrometer, constructed on Mr. 

 cle la Hue's principle, with Professor Clifton's improvements, together 

 with a chloride of silver battery of 60 cells, for the purpose of main- 

 taining the potential of the quadrants at a certain point, gave great 

 satisfaction during the year, aud was found to be a marked improve- 

 ment upon the older form of the instrument. 



On September 2, during a high wind, a parfc^of the instrument was 

 accidentally set on fire by the gas-burner, and the apparatus narrowly 

 escaped destruction. 



Before re-starting the instrument it is proposed to make some 

 minor alterations, suggested by experience, in the recording appara- 

 tus, &c. 



The portable Thomson electrometer (White Xo. 53) having been 

 put in thorough order, has been lent, in accordance with instructions 

 received from the Meteorological Council, to the Hon. Ralph 

 Abercromby, for the purpose of making observations on the Peak of 

 Teneriffe. 



Mr. Abercromby visited the Observatory for the purpose of fami- 

 liarising himself with the use of the instrument, the scale value 

 having previously been redetermined, by the kindness of the Chair- 

 man, at his laboratory in Portland Place. 



III. Solae Observations. 



The sketches of Sun-spots, as seen projected on the photoheliograph 

 screen, have been made on 180 days, in order to continue Schwabe's 

 enumeration, the results being given in Appendix II, Table IY. 



Transit Observations. — 347 observations of solar and 80 of sidereal 

 transits have been taken, for the purpose of keeping correct local time 

 at the Observatory, and the clocks and chronometers have been com- 

 pared daily. 



The following clocks, French, Shelton K. 0., Shelton 35, and the 

 chronometers, Molyneux No. 2125, Breguet Tso. 3140, and Arnold 80, 

 are kept carefully rated as time-keepers at the Observatory. 



The mean-time clock, Dent 2011, was bolted to the wall of the 

 chronometer-room for use in daily comparisons with the chronometers 

 on trial. 



R 2 



