1867.] Observations of Temperature during two Eclipses. 421 



II. " Observations of Temperature during two Eclipses of the Sun (in 

 1858 and 1867)/' By John Phillips, M.A., LL.D., D.C.L., 

 F.R.S., Professor of Geology in the University of Oxford. Re- 

 ceived April 3, 1867. 



On the 15th of March 1858, occurred an annular eclipse of the sun, whose 

 central line of shadow passed near the village of Steeple Aston, a few miles 

 north of Oxford. Ample preparations were made for observing it by resi- 

 dents in Oxford, and they were met on the ground by many persons from 

 a distance ; Mr. Lassell being one of the party, there was no lack of tele- 

 scopic power. The day was unfavourable — cold and cloudy, with some 

 occasional feeble and delusive gleams, scarcely permitting a sight of the 

 progress of the eclipse, which, however, was obvious enough by the grow- 

 ing and diminishing darkness. Under these circumstances I devoted my 

 principal attention to three thermometers, carefully selected and compared 

 beforehand — one mercurial with blackened bulb, another mercurial with 

 clear bulb (these were placed in an open space exposed to the sun) ; the third, 

 a minimum- spirit thermometer, tint red, was placed in a shaded situation. 

 The observations began at ll*" SO'" and lasted till 2^ 30"*, thus including 

 the whole period of the eclipse, which began at 1 1^' 35™, reached the maxi- 

 mum of obscuration at O'' 54™, and ended at 2^ 1 1"*. The apparent semi- 

 diameters of the sun and moon were so nearly equal that the eclipse was 



( 997 \ 

 ). The observations were recorded as follows : — 

 loooy 



Hour. 



Thermo- 

 meter in 

 sliade. 



Clear 

 thermo- 

 meter in 



sun. 



Dark 

 thermo- 

 meter in 



sun. 



Eemarks. 



h m 











11 30 



490 



51-6 



58-0 



Gleams, 



35 



Beginning of eclip 



se. 



Grleams. 



45 



490 



500 



55-0 



12 



48-5 



49-5 



54-5 





15 



48-5 



490 



52-0 





30 



48-1 



48-5 



50-0 





45 



48-1 



48-5 



49-2 





54 



This was 



the moment of greatest obscuration. 



1 



47-5 



47-5 



47-5 



Lowest temperature. 



15 



47 -5 



47-5 



48-0 





30 



47-6 



480 



48-8 





45 



48-0 



49-4 



51-0 





2 



48-3 



49-8 



51-7 





11 



End of eclipse. 







15 



49 



.50-5 



53-1 



Rain began. 



30 



48-0 



49-5 



51-2 



Rain continued. 



Mean . . . 

 Max. ... 

 Min. ... 

 Eange ... 



48- 3 



49- 

 47-5 



1-5 



49-6 

 51-6 

 47-5 

 4-1 



51-5 

 58-0 

 47-6 

 10-4 





