Page:Proceedings of the Royal Society of London Vol 69.djvu/230

214 Briggs and Mrs. Newall for the exposures they had to make with their respective instruments for the reappearing flash.

These two observations were recorded in terms of the metronome beats, and were connected with the chronometer readings by my noting on the chronometer the instant at which the last call of the count with the metronome was made by the time-keeper.

The metronome was adjusted to beat seconds the night before the eclipse, and as set it lost one beat in 6 minutes. It was tested about a quarter of an hour before the eclipse, and again after the eclipse, and was found in several trials to lose between one and two beats in 6 minutes.

The photographs of the disappearing and reappearing crescents afford a check on these signals called both by Dr. Wallace and myself, but the discussion is not yet completed.

The following summary may be given of the records kept between April 24 and May 22 :

Becloudedness. Out of 23 days on which record was kept of the becloudedness of the sky near the zenith between 12 and 1 o'clock midday the eclipse occurred at 12.22 P.M.

1 was absolutely free from cloud and haze (May 1). 4 were free from cloud, but more or less hazy. 8 were completely overcast. 10 were more or less cloudy (including the day of the eclipse).

Temperature and Moisture. The temperature was recorded for wet- and dry-bulb thermometers in the verandah :

Time of day

6 A.M.

Midday.

Evening (about 9 P.M.).

Number of days on which readings were recorded

} .'

11

7

Thermometer

Dry.

Wet.

Dry.

Wet.

Dry.

Wet.

Average

72 76 69

71

74 67

84 86 80

78 80

74

76

77 75

74 C 75 72

Highest

Lowest

Piain. Records on 21 days : ^

On only 2 out of 21 days, on which record was kept, was there rain between 6 A.M. and midday. On 8 days there was no rain. On 13 days there was rain in the afternoon or night.