Total Eclipse of the Sun, 1901, May 18. 



241 



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. 



VOL. LXIX. S 



