Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/340

 riodick course of the said spots, yet did they not alter the opinion of our friend, so as to make him believe, that they were any essential and fixed cause of those deviations, but he continued to hold, that all the apparent alterations derived themselves from those accidental mutations: in like manner, just as it would happen to one that should from far distant Regions observe the motion of our Clouds; which would be discovered to move with a most swift, great, and constant motion, carried round by the diurnal Vertigo of the Earth (if haply that motion belong to the same) in twenty four hours, by circles parallel to the Equinoctial, but yet altered, in part, by the accidental motions caused by the winds, which drive them, at all adventures, towards different quarters of the World. While this was in agitation, it came to pass that Velserus sent him two Letters, written by a certain person, under the feigned name of * Apelles, upon the subject of these Spots, requesting him, with importunity, to declare his thoughts freely upon those Letters, and withall to let him know what his opinion was touching the essence of those spots; which his request he satisfied in 3 Letters, shewing first of all how vain the conjectures of Apelles were; & discovering, secondly, his own opinions; withal foretelling to him, that Apelles would undoubtedly be better advised in time, and turn to his opinion, as it afterwards came to pass. And because that our Academian (as it was also the judgment of many others that were intelligent in Natures secrets) thought he had in those three Letters investigated and demonstrated, if not all that could be desired, or required by humane curiosity, at least all that could be attained by humane reason in such a matter, he, for some time (being busied in other studies) intermitted his continual observations, and onely in complacency to some friend, joyned with him, in making now and then an abrupt observation: till that he, and after some years, we, being then at my * Country-seat, met with one of the solitary Solar spots very big, and thick, invited withal by a clear and constant serenity of the Heavens, he, at my request, made observations of the whole progresse of the said spot, carefully marking upon a sheet of paper the places that it was in every day at the time of the Suns coming into the Meridian; and we having found that its course was not in a right line, but somewhat incurvated, we came to resolve, at last, to make other observations from time to time; to which undertaking we were strongly induced by a conceit, that accidentally came into the minde of my Guest, which he imparted to me in these or the like words.

In my opinion, Philip, there is a way opened to a business of very great consequence. For if the Axis about which the Sun turneth be not erect perpendicularly to the plane of the Eclip-