F 3
the Open Air, the range of relative humidity is actually greater. It is hoped however that the excessive dampness during the summer months may be reduced by a heating element which has recently been installed along the outside of the inner wall at a height of 11 feet from the floor. It is to be controlled by a thermostat, but the instrument sent out was found to be unsatisfactory so has been sent back to the makers for alterations.
Beginning with 1925, February 1st, the records have been standardized only by eye observations on entering and leaving the room for the purpose of changing the seismograph sheets.
II.-METEOROLOGICAL INSTRUMENTS,
Barometers.-The Marvin compensated syphon barometer has worked satisfactorily.
The station barometer No. 1323 and the large Casella barometer were compared with the Observatory Standard on May 19th.
Beckley Anemograph.-This instrument was oiled and the orientation of the vane checked once a month.
Dines-Barendell Anemograph.-The bearings of the vane were oiled and its orientation checked once a month. The spindle of the float was cleaned and oiled once a week.
The Mean monthly results of comparisons with the records of the Beckley Anemograph from 1910-1923 are given in the following table, together with the results for 1924:--
Month Mean 1910-1923 1924 January, 1'96 2:05 February, 1'64 1'79 March, 2.01 2'07 April, 1.57 1.70 May, 2:05 June, 2.16 2.49 July, 2.13 2.II August, 2:07 2.60 September, 2.22 2°12 October, 2.18 2'46 November, 2:05 2.18 December, 1'96 2.15 Year 1'92 1'94 2:06 2'07Factor for converting the actual run of the Beckley Anemograph cups to velocities recorded by the Dines Pressure Tube Anemograph.
Factor (Dines ÷ Beckley).