Page:Proceedings of the Royal Society of London Vol 69.djvu/257

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Total Eclipse of the Sun, 1901, May 18.
241

Local time.

Beginning of eclipse

hrs.

10

11


mins.

48


sees.

11


17

11

30 11

45

12

Beginning of totality

12 12 12 13


20 19 26 25


30 50


End of totality... 13

40

End of eclinse .

13 13


53

58


Beading of thermometer.


88-8 86-0 85-0 84-3 81-8 79-0


84-9 84-9

88-0


As the temperature usually rose from 90 to 92, there would seem to have been a fall of temperature of from 10 to 13 due to the eclipse.

The duration of the eclipse was observed by Captain Oldham as 6 m 20 s- 5, and by Dr. Nimmo as 6 m 21 S> 5. These times agree with those obtained by the Dutch observers at Karang Sago, who give for the duration 6 m 22 s .* These times are 10 s less than that given in the Nautical Almanac, but agree closely with a prediction kindly forwarded by Dr. Downing (based on a value of 15' 31 "'47 for the mean semi-diameter of the Moon, derived from a recent discussion of eclipse observations), viz., 6"' 20 3 .

At the commencement of totality at Aoer Gadang a signal was flashed across to the Dutch eclipse camp by the " Pigmy " search-light, thus giving them a warning 16 s before totality occurred at their station.

During totality the sky was much darker than at Ovar in the eclipse of 1900, May 28. Venus, Mercury, and Aldebaran were seen. The corona appeared to be white ; the polar plumes and the prominences were distinctly seen.

Development of the Photographs. As stated in a previous paragraph, a fully equipped dark room was taken out to Sumatra. It was found before the eclipse that considerable care was needed in the develop- ment of photographs owing to the high temperature. Immediately after the eclipse the " Pigmy " went to Padang, returning the next day with 250 Ibs. of ice. The photographs were developed on May 19 and five following nights. Thanks to the untiring assistance of Mr. Curtain, gunner of the " Pigmy," the development of the thirty-seven

  • ' Proceedings of the Koninklijke Akademie van Wetenschappen te Amster-

dam, 1901,' p. 87.