Observations on the Annulcir Solar Eclipse. 131 



From the above tabulated results it will be observed, that from 

 the first period of observation (10^ 45™), the instruments in 

 all their relative situations gradually rose in temperature, until 

 jh ggm^ jj|- ^vhich time they had obtained their maximum point, 

 except the one exposed to the air and sun's rays, whose indica- 

 tions were influenced by passing currents of air by which it was 

 at intervals depressed. At 1^ SS'^.T the moon's limb was ob- 

 served to enter on the solar disc, and a few minutes after that ob- 

 servation the thermometers were noted. Those in the box under 

 the direct influence of the solar heat, had already become de- 

 pressed ; while that in the northern shade remained stationary 

 until near two o'clock, when it also indicated a depression. The 

 three exposed to the sun's rays had continued their progressive 

 descent from the commencement of the eclipse. 



At 3^ the annular phase was central, and the instruments 

 most clearly indicated an extensive depression from the time 

 of the first contact of the limbs, and still continued to fall 

 until some minutes after that hour, when those exposed to the 

 solar rays attained their minimum temperature ; not so, how- 

 ever, the thermometer in the shade, whose indications of its 

 lowest point did not occur until 3*^ 16^. 



The annular phase having ended at 3^ S'^.S, and the body of 

 the moon withdrawn itself from the sun's disc, so as to permit 

 the intercepted rays to fall to the earth, the instruments quickly 

 indicated the change, and continued to rise as the eclipse passed 

 off*. They attained their second maximum at 4*^ 24™, the time 

 at which the eclipse ended. The sky now became partially over- 

 cast with thin attenuated clouds, dispersed over the solar disc, 

 and intercepting the solar radiation, farther experiments were 

 therefore discontinued. It may, however, be mentioned, that 

 during the time of the eclipse, and whilst the observations were 

 recorded, the sun presented a uniformly clear disc, and the atmo- 

 sphere remained as nearly as possible in the same state. 



