F 2
Mean Monthly Temperature and Relative Humidity in the Underground Chamber and in the Open Air,
during the year 1926.
In Underground Chamber. In the Open Air. Excess of Underground Chamber over Open Air. Mouth 1926. Temper-ature Relative Humidity Temper-ature Relative Humidity Temper-ature Relative Humidity January, 71.9 54 61.1 72 February, ... 70.7 61 60.0 82 +10.7 -18 March,... 70.5 70 63.8 82 +6.7 -12 April, 71.4 81 68.9 87 +2.5 -6 May, 73.4 88 76.1 83 -2.7 +5 June,. 75.3 89 77.8 83 -2.5 +6 July... 77.8 96 82.1 81 -4.3 +15 August,.. 79.1 94 82.1 83 -3.0 +11 September 79.6 92 81.5 80 -1.9 +12 October, 78.0 74 75 75 +3.0 -1 November, 75.9 71 68.9 73 +7.0 -2 December, 73.5 66 62.7 69 +10.8 -3 Range...... 9.1 42 22 18II. METEOROLOGICAL INSTRUMENTS.
Barometers. The Marvin compensated syphon barometer has worked satisfactorily, except that the buzzer for overcoming inertia and friction, and the time-break apparatus, have failed occasionally. In the month of February, a combined buzzer and time-break apparatus was fitted by Mr. Evans.
The coils of an electric bell were screwed to the base plate near the suspension thread of the conical steel float and a one-inch nail inserted in the suspension thread at the same height as the coils. The minute signal circuit to the thermograph buzzer was lead through these coils, which therefore acted as a buzzer and vibrated the nail on the float suspension. The hourly signal was also lead through the coils thus attracting the nail and causing an appreciable mark on the register.
This scheme works well provided the battery strength remains fairly constant and the thermograph buzzer works well.
The station barometer No. 1323 and the large Casella barometer were compared with the Observatory Standard on April 30, and June 26.
Beckley Anemograph.-This instrument was oiled and the orientation of the vane checked once a month.