XXII. But the first person we have any account of, who observed these spots, was Father Christopher Scheinerus a jesuit, who applied himself to it with such diligence, that between the years 1611 and 1627 he had made fourteen hundred observations of them, which he gives an account of in his _Rosa Ursina_. The celebrated Galileus Galilei began also to observe them about the same time that Scheinerus did; and since them, the most laborious astronomers of the last and the present century, have applied themselves to making the same observations; so that this is a matter, which at present there is not the least doubt about; and although some have entertained suspicions whether these spots were in the body of the sun, or at a little distance from it; others have removed those difficulties, by demonstrating, that they are inherent in, and exist on, the superficies of the sun; for they not only revolve in the same proportion the sun does, but they most probably remain upon it during the whole time it takes in making an intire revolution, which it does in twenty-seven days, and they are to be seen compleat for half the time of that period; which could not happen, if the spots were inferior to the star. XXIII. And whether these spots are sooty or smoaky vapours, which arise from the great furnace of the sun, as some think, or are any other different thing; it is clear, that during their continuance, the light and the heat of it reflected on the lower elemental regions, must be diminished in proportion to the size and number of the spots; and to this cause may be attributed, some of the notable diminutions of the light and heat of the sun, which we find recorded in history, provided they were not occasioned by some obstructions in the atmosphere. Mayolus tells us, that in the time of the emperor Justinian, the light of the sun for the greatest part of a year was so dim and faint, that it scarce exceeded that of the moon; and Plutarch tells us, that at the time of the death of Julius Cæsar, the light of the sun was equally feeble for a whole year together; which Virgil also takes notice of in the following verses of the Second Book of his Georgics: _Ille etiam extincto miseratus Cæsare Romam_ _Tunc caput obscura nitidum ferrugine texit:_ _Impiaque æternam timuerunt sæcula noctem._ PARADOX VII. _The Rays of the Sun reflected on a Concave Body, produce a greater Heat in Winter than in Summer, which Heat is greater still in Proportion to the coldness of the weather._ SECT. VII.