826 APPENDIX. [No. XXIV. 



No. XXIV. 



THE ECLIPSE OF THE SUN. 1858. 



To the Editor of the ' Morning Chronicle.' 



Sir, — I am afraid that your correspondent may think he has good cause 

 to accuse me of want of courtesy in not having supplied to him an account 

 of the experiments on the light of the eclipse, but the observations exceeded 

 160, and at the moment I could not compress them into a form suitable 

 for your paper, or I should have had great pleasure in giving the details at 

 once. The great interest which naturally, however, belongs to this grand 

 natural phenomenon, induces me to send a short account of some observa- 

 tions made at Blisworth upon the darkness which marked the progress of 

 the obscuration, in the hopes that it may not be unacceptable to many of 

 your readers. It has occurred to me that my "abstract photometer" 

 might do good service ; for whether the weather was fine, or whether it was 

 cloudy, yet it was calculated to give us an insight into the extent to which 

 the sun's light might be veiled from the surface of the earth. 



The photometer consists of a wedge of neutral tint coloured glass, 

 cemented by Canada balsam to a similar wedge of colouiless glass, and the 

 solid which results from the junction of the two 

 prisms is divided into degrees, each of which is equal 

 to the capacity of the one-hundredth of an inch of 

 pure bromine, so that the short account now given 

 may be compared by future philosophers with the 

 results of subsequent eclipses hundreds or thousands 

 Fio. 18. of years hence, if they do but know the length of 



Smee'B Photometer. ^^ EngUsh inch. Armed with this instrument, I 

 proceeded to Blisworth, where I found a field con- 

 veniently located, which had been secured by some of my friends, and 

 where chronometers and aU other instruments for accurate research had 

 been provided. I determined to take three sets of observations : the first, 

 of the light of the horizon, at a spot where a tree cut sharply the line to 

 the south ; the second, of the light of the ground at oui- feet ; and the 

 third, the light of the sky overhead : and I anticipated that I should 

 be able to test by the vigorous proof of scientific truth the wonderful 

 stories which are told of eclipses, which appeared to my mind as the 

 results of overheated imaginations, or of stories fit for an appendix to the 

 curious Travels of Baron Munchausen. 



In the morning, at half -past eight, the sky showed a light which was 

 veiled at 17:* but at the commencement of the eclipse the clouds were 

 so dense that the horizon was obscui-ed at 1415. Fi'om this time till 

 12h. 53', the light continually diminished to 11. The next obsei-vation was 

 taken at Ih. 2', when it stood at nearly 14, from which it rose to 15 at 

 2h. 16', at the termination of the observations. I need not here aUude to 

 the rises and f aUs of light as the clouds became thinner or denser, as it 

 is sufficient to notice that the horizon lost Ught continually from the 

 beginning to the total, and gained from the total to the termination. 



This and the following numbers refer to the degrees of the photometer. 



