332 PHILOSOPHICAL TRANSACTIONS. [aNNO I676. 



reason of its fineness, and the too great height of the sun, he could not take 

 any measures to determine its place and latitude by ; and that, while the spot 

 continued one, as it was July 25, he measured to the middle of it ; as also when 

 the pieces were divided, but not far disjoined : afterwards, when they were sepa- 

 rated considerably, he observed the middle of the larger spot, which was to the 

 south, apparently, I suppose ; but really north : for so only his observations will 

 agree with those of Mr. Flamsteed exactly. 



Hence it seems very evident, says Mr. Flamsteed, that the spot's way was not 

 inclined to the ecliptic six or seven degrees, as Scheiner and some others make 

 it, but much less, by the joint consent of the observations of both our observers, 

 Mr. Halley adds, that considering the motion of the spot across the sun's disk, 

 as both their observations give it, it appears, that the latitude was not so great at 

 its entrance into the sun as in the middle of him. And by Mr. Flamsteed's 

 observation it was greatest on the 1st of August, and then again inclining to- 

 wards the ecliptic. If you grant this, it will follow, infers Mr. Flamsteed, that 

 the sun's axis was inclined to the plane of the orbis magnus ; but the quantity of 

 this inclination must not be very great. The nodes of the sun's equinox and 

 ecliptic he guesses to be not far from the beginning of Cancer and Capricorn ; 

 and that from Cancer to Capricorn the earth is north of the sun's equator, from 

 Capricorn to Cancer, south of the same : and the period of the sun's revolution, 

 in respect of the fixed stars, 25 days, 9 4- hours sufficiently exact. Of which 

 things, these two observers say, they might have been more certain, had not the 

 spot in its passage broken into so many parts, and those often varied their posi- 

 tions to each other. These conjectures, though probable, yet when another of 

 the like phsenomena appears, will still deserve the further consideration of the 

 curious. 



^n Extract of Signor CassinVs Letter concerning a Spot lately seen in the Sun: 

 together ivith a remarkable Observation of Saturn, made by the same. N° 128, 

 p. 689. Translated from tlie Latin. 



We here observed the same solar spot as Mr. Flamsteed, from August 6 to 

 ]4 N. S. ; and by comparing our observations, we found that it was in the mid- 

 dle of its course, in the sun's apparent disk, about midnight after the 8th of 

 August, at the apparent distance of 3 minutes from the centre towards the south. 

 It is divided into several parts, which separate from each other daily towards the 

 north and south; so that besides their com mensuration about the sun's axis, all 

 the parts have a direct motion of their own among themselves. I think this 

 spot is different from that which we observed in the preceding month of June. 

 For since that had the middle of its course in the apparent disk of the sun, on 



