No. XXIV.] APPENDIX. 327 



The illumination of the ground presented far more interesting and 

 important variations. At the commencement of the eclipse the illuminat- 

 ing power was 11 ; it varied with the depths of the clouds, but gradually 

 receded to 8*5 at 12h. 53'. At 12h. 55' it dropped to 8*3 ; at 12h. 58' it 

 reached 8 ; at 12h. 59' it was as low as 7*25. This was about the minimum 

 of light and maximum of darkness, when suddenly, in little more than a 

 minute afterwards, the earth became illuminated, and two or three seconds 

 after 1 o'clock the light rose to 10, and continued to rise with the varia- 

 tions of the clouds till 2h. 15', when it stood at 12*5. This illumination of 

 the earth was a wonderful natural phenomenon : the country people called 

 out, " It's all over ! " and to see the ground brightly lighted whilst the sky 

 remained in great darkness was a surprising, and to me an unexpected, 

 appearance. 



The sky was observed as near the zenith as convenient : at the com- 

 mencement it was equal to 14*25 ; from this it gradually, with variations 

 according to cloud, diminished to 11*75 at 12h. 50', and then rapidly 

 dropped till 1 o'clock, when it stood at the lowest amount, 9*25. At Ih. 2' 

 it rose to 12*5, many seconds later than the rise of the illumination of the 

 earth, so that the earth, brightly illuminated for some seconds, remained 

 with a dark canopy overhead, and this peculiarity appears to give a 

 marked character to the darkness of an eclipse which differs from other 

 obscurations. 



From these observations it is apparent that a great diminution of light 

 gradually occurs from the commencement to the totality, at which point 

 it very rapidly further declines ; after the totality it almost suddenly 

 rises, and in fact so rapidly as to appear like a scene at a theatre suddenly 

 illuminated, from which time the light increased to the end of the eclipse. 



To the wondermongers who put all, the birds to roost, I may state that 

 the lark sang in the air at 12h. 47' ; that other birds flew about and chirped 

 to 12h. 50' ; that larks rose in full song as late as 12h. 52', and remained in 

 full song to 12h. 55', at which time the cocks were heard to crow ; even 

 the birds in the hedges whistled at 12h. 58', and, in fact, continued their 

 songs and flights from the beginning to the end of the eclipse : and if there 

 was an interval in their proceedings, it could not have been for more 

 than three minutes. The sun became visible at Ih. 0' 21", and again at 

 intervals till Ih. 57', when the light of its disc amounted to 18*25. 



The barometer did not sensibly vary. I ascertained that the difference 

 between the dry and wet bulbs lessened at the time of the greatest cold 

 from about 3 to 1. 



Although these results are by no means so perfect as could be desired, 

 yet they are of considerable interest, and I trust they will lead on a future 

 occasion to such observations that the variations of light and darkness 

 may be accurately detailed. 



I am, Sir, your obedient servant, 



7, FINSBTJRY CIRCUS, ALFRED SMEE. 



March 16. 



