THE DARK DAY OF 1780. 143 



had spread uniformly over the heavens, there was no remarkable 

 deficiency of light. — If any one chuses to make an experiment 

 for himself to illustrate the matter, let him take a few panes of glass, 

 and place them at a small distance from each other in such a manner, 

 that the sun may shine directly through them all ; in this case he will 

 find that the rays of light are much more obstructed than they will be 

 in passing through a single glass, equal in thickness to all the others. 

 — The reason is obvious. — The reflection of light is from the 

 surfaces of transparent bodies, and not from their interior parts. 



Various suppositions have been made respecting this subject. — 

 Some have supposed, that the earth was passing through the tail 

 of a comet ; to this it is a sufficient answer that stars are visible 

 through the tails of comets, it is therefore impossible, that this cause 

 should obscure the lustre of the sun. — A writer has appeared under 

 the signature of Viator, in the Independent Chronicle, May 25th, who 

 asserts that upon examining the rain water in tubs " I found a light 

 " scum over it which rubbing between my thumb and finger, I found 

 "to be nothing but the black ashes of burnt leaves. — The water gave 

 '' the same strong smell, which we had observed in the air, and con- 

 " firmed my opinion, that the smell mentioned above, was occasioned 

 " by the smoke or very small particles of burnt leaves, which had 

 " obscured the hemisphere for several days past, and were now 

 " brought down by the rain. — I believe it is the first time that it ever 

 came within the compass of a human imagination to suppose, that 

 the haziness of the sky in warm weather was occasioned by ashes 

 being lodged in it, which needed the assistance of rain to bring it 

 down — Just as probable is the theory which accounted for the dark- 

 ness, from this circumstance, that the sun and Jupiter were then in 

 the quartile aspect. More plausible, but not more just, was the 

 opinion of a gentleman of learning, who supposed that the nucleus of 

 a comet intervened between the earth and the sun, and occasioned a 

 solar eclipse. — There are various phcenomena which by no means 

 correspond with this opinion. . The clouds were seen continually 

 rising to obscure the hills which is sufficient to account for the dark- 

 ness ; and the tides did not rise to an unusual height, as they would 

 have done, had a compact body of such magnitude as a comet, been 

 so near the earth, in such a situation, as to give us darkness instead 

 of day. — It is in vain to assign the rapid motion of a comet, as a 

 reason why the tides should not rise any higher than usual ; for though 

 it was but a short time in conjunction with the sun, yet it's motion 



