An essay on comets, their nature, the laws of their motions, the cause and…

That the Tails of Comets are extremely rare, is apparent from this; the Fixed Stars appearing so plainly through' them.

That the Tails of Comets are extremely rare, is apparent from this; the Fixed Stars appearing so plainly thro' them.

The Atmosphere of Comets, as they descend towards the Sun, is very sensibly diminished by their vast running out, that they may afford Matter to produce the Blaze. Hevelius has observed, that their Atmosphere is enlarged, when they do not so much run out into Tail.

Sir Isaac Newton has an Apprehension, which is a little surprising, That those Vapours which are dilated, and go off in the Blazes of Comets, and are diffused through' all the Celestial Regions, may by little and little, by their own proper Gravity, be attracted into the Planets, and become intermingled with their Atmospheres. As to the Constitution of such an Earth as ours, it is necessary there should be Seas; thus, for the Conservation of the Seas, and Moisture of the Planets, there may be a necessity of Comets, from whose condensed Vapours, all that Moisture, which is consumed in Vegetations and Putrefactions, and so turned into dry Earth, may by degrees be continually supplied, repaired, and recruited. Yea, he has a suspicion, that the Spirit, which is the finest, the most subtle, and the very best part of our Air, and which is necessarily requisite unto the Life and Being of all Things, comes chiefly from Comets. If this be so, the Appearance of Comets is not so dreadful a thing, as the Cometomantia, generally prevailing, has represented it.

Sir Isaac Newton has an Apprehension, which is a little surprizing, That those Vapours which are dilated, and go off in the Blazes of Comets, and are diffused thro' all the Celestial Regions, may by little and little, by their own proper Gravity, be attracted into the Planets, and become intermingled with their Atmospheres. As to the Constitution of such an Earth as ours, it is necessary there should be Seas; thus, for the Conservation of the Seas, and Moisture of the Planets, there may be a necessity of Comets, from whose condensed Vapours, all that Moisture, which is consumed in Vegetations and Putrefactions, and so turned into dry Earth, may by degrees be continually supplied, repaired, and recruited. Yea, he has a suspicion, that the Spirit, which is the finest, the most subtle, and the very best part of our Air, and which is necessarily requisite unto the Life and Being of all Things, comes chiefly from Comets. If this be so, the Appearance of Comets is not so dreadful a thing, as the Cometomantia, generally prevailing, has represented it.