626 PHILOSOPHICAL TRANSACTIONS. [aNNO 17 U. 



torn part was only compliments for his writing to him, being a stranger, &c. 

 after which it follows in these words. 



*• I writ also to Mr. Townley at that time my opinion in brief of the sun's 

 spots, (which you conceive to be stars,) and it seems he, or Mr. Kay, writ to 

 the same purpose to you, desiring your opinion : which you freely deliver ; for 

 which I cannot but commend you, and especially for preferring reason before 

 any man's authority. Yet give me leave (pace tua amice desideratissime) to 

 speak my mind likewise freely concerning these appearances. I do not value 

 the authority of Galilaeus (though reputed the greatest speculative mathema- 

 tician in Europe) nor yet Kepler (though astronomorum facile princeps) further 

 than either demonstrative, or the most probable reasons confirm their opinions. 

 Nor will I stick to subscribe to the man whosoever shall bring better reasons 

 for his opinion. I must acknowledge you say more for the stellifying of these 

 solar obscurities, than I have heard before ; yet I conceive not sufficient, either 

 demonstratively or probably to countermand those which Galilaeus, Kepler, and 

 others have produced to the contrary ; nor yet such as can be cleared from such 

 objections, as reason, demonstration, and observation may lay against them. 

 My occasions will not admit a full disquisition hereof at this time ; yet some 

 thing I would say for the present, the better to furnish you where to object 

 when I see you ; that so by diligent inquisition, the desired truth may (may 

 we have that happiness) be better found out by us. 



" I have often observed these spots ; yet from all my observations cannot find 

 one argument to prove them other than fading bodies. But that they are no 

 stars, but unconstant (in regard of their generation) and irregular excrescences 

 arising out of, or proceeding from the sun's body, many things seem to me to 

 make it more than probable. 



** For first, for their form ; they are seldom round, but of irregular shapes, 

 and, as I have often seen, one side or end of the spot more thin than the rest, 

 like to a certain misty darkness, and by degrees thicker, grosser, and darker, 

 nearer to the main body of the spot ; just as the smoke of some pitchy fire, 

 which is in one part very gross, and in another more rare and thin, turning at 

 last into meer air : or like a cloud, fog, or mist, more thick, dark, and gross 

 in the midst ; and more thin, fluid, penetrable, and transparent towards the 

 sides ; which I suppose is not compatible with any of the stars. 



" Secondly, for their colour : The lightness thereof difFerenceth them from 

 stars or planets ; they being never of such absolute darkness as I observed Venus 

 the '24th of November last : though I have seen spots sometimes little less than 

 she, yet always of afar paler and whiter colour, looking (at least in some parts) 

 like some thin dissipated substance. 



