effect by the poet Whittier.  The Connecticut Legislature was in session on that day, and as the darkness came on and grew more and more dense, the members became terrified, and thought that the day of judgment had come; so a motion was made to adjourn.  At this, a Mr. Davenport arose and said:  “Mr. Speaker, it is either the day of judgment, or it is not.  If it is not, there is no need of adjourning.  If it is, I desire to be found doing my duty.  I move that candles be brought and that we proceed to business.”  Mr. Davenport’s suggestion was taken, candles were brought in, and business went on as usual.  As to the explanation of this phenomenon, scientists have been much puzzled.  It was plain from the falling of the barometer that the air was surcharged with heavy vapor.  The darkness then, it might be said, was only the result of a dense fog, but the question of the cause of so remarkable a fog was still unanswered.  Omitting this unascertained primary cause, then, Professor Williams, of Harvard College, who subsequently made a thorough investigation of the matter, gave it as his opinion that this unprecedented quantity of vapor had gathered in the air in layers so as to cut off the rays of light, by repeated refraction, in a remarkable degree.  He thought that the specific gravity of this vapor must have been the same as that of the air, which caused it to be held so long in suspension in the atmosphere.  In this case the extent of the darkness would coincide with the area of the vapor, and it would continue until a change in the gravity of the air caused the vapors to ascend or descend.  In some places when the darkness cleared it was as if the vapor was lifted and borne away by the wind like a dark pall, and in others, after a period of intense darkness the atmosphere gradually lightened again.  In our day, a phenomenon of this kind would be thoroughly investigated to its most remote possible cause; but then owing to the sparse settlement of the country and the difficulties of travel, the investigation of distant causes could not be made.  Large fires may have prevailed that spring in the forests of Western New York and Pennsylvania—­a region then an absolute wilderness—­the smoke of which was borne through the upper regions of the atmosphere, to fall when it came to a locality of less buoyant air, down to the lower strata.  We say these fires may have recently preceded this day, and served as its sufficient cause, but we have only presumptive evidence that they did occur.  Had Professor Williams entertained a supposition of the previous existence of such fires, he had then no means of verifying it, and long before the advent of railroads and telegraphs, or even of stage lines, the scientific theories of the dark day had passed from the general memory.