632 PHILOSOPHICAL TRANSACTIONS. [aNNO I67I. 



at right angles In the common focus of the two glasses, and in the axis of the 

 telescope : "and having directed it toward the sun, he so turned it, that letting 

 it afterwards rest, one might see the centre of the sun, according to one of 

 these threads, advance westward, this same thread marking in the sun a cir- 

 cle parallel to the equator ; and the other thread marked the circle of declina- 

 tion ; or the horary circle of the said sun. Thus he noted the situation and 

 motion of the spots. 



On the twelfth of August he observed them from the time of sun-rising, and 

 perceived them now nearer his centre. He continued exactly to observe them 

 with a large telescope, from six o'clock in the morning to seven. The first 

 was composed of two others almost round, and conjoined. The second repre- 

 sented the shape of a scorpion. The third was round. And they were all 

 three environed with a coronet, which was composed of abundance of little 

 obscure points. At 48 minutes after eight o'clock, the figure of the scorpion 

 was seen divided into several pieces, as if his tail and arms had been cut off. 

 The northern point appeared no more, there remaining none but those on the 

 south side ; and the length of the enclosure of all the spots, comprehended 

 between the extremities, was of one minute and 1 5 seconds, and the breadth 

 of 30 seconds. The same 12th day, at six in the evening, he found no great 

 change in the first spot. The other two were severed into five distinct ones, 

 compassed about with a coronet. 



The 13th of August they were observed again. 



In one day and a half these spots have run through very near the third part 

 of the sun's apparent semidiameter, which gives an arc of IQi degrees of the 

 circumference of the sun's body ; and consequently their diurnal motion about 

 the sun's axis has been of 13 degrees ; and the time of their periodical revolu- 

 tion, as far as we could conjecture in so little time, must be about 2/ days and 

 a half : which yet will be more exactly determined by observations of a longer 

 time. And in 6 or 7 days hence they may probably arrive at the sun's 

 edge. 



So far the French academists. To which we now add ; 1. That since their 

 observations were made public, we had notice sent us from the above-men- 

 tioned Dr. Fogelius at Hamburgh, that Mr. Picard had observed at sea a spot 

 - in the sun from the third of August n. st. to the igth of the same inclusively. 

 2. That several observers at London have seen one of those spots arrive at the 

 sun's eastern limb, on the same day that Signor Cassini predicted in the rela- 

 tion above delivered they should return, if they continued. 



