Page:Philosophical Transactions - Volume 001.djvu/110

 hold each 25 or 30 pounds, and these they expose to clear Nights; and if there be any impurity remaining, it will fall to the bottom: Afterwards they break the Pots, and dry the Salt in the Sun. One might make vast quantities of Saltpetre in these parts; but the Country People seeing that We buy of it, and that the English begin to do the same, they now sell us a Maon of 6 pounds for two Rupias and a half; which we had formerly for half that price.

This excellent Dantiscan Astronomer, Hevelius, in his Prodromus (by him so call'd, because it is as a Harbinger to his Cometography, which hath already so far passed the Press, that of twelve Books there are but three remaining to be Printed) gives an Account of the Observations he hath made of the First of the two late Comets; reserving those he hath made of the second, for that great Treatise, where he also intends to deliver the Matter of this first more particularly and more fully then he hath done here.

In this Account he represents the Rise, Place, Course, Swiftness, Faces and Train of this Comet, interweaving his Conceptions both about the Region of Comets in general (whether it be the Air, or the Æther?) and the Causes of their Generation: In the search of which latter, he intimates to have received much assistance from his Telescope.

He observed this Comet not before Decemb., (though he conceives it might have been seen since Novem. 23.st.n) & he saw it no longer then Feb. : though several others have seen it both sooner, and later: and though himself continued to look out for it till March 7. st.n. but fruitlesly, whereof he thinks the reason to have been its too great distance and tenuity.

Rh