-r- -^^-.-Jt n 



.2.2 



M ATHEM 



AND 



It hath been mentioned before, that it was on Thurfday 



June I ft, that M , .^^^^ 



No rn ton with ^dGfign to continue with MnRittenhoufe 'till 

 the tranfit fliould be over. The profped before us was 

 very difcouraging. That day, and feveral preceding, had 

 been generally overcaft with clouds, and frequent heavy 

 rains J a thing not very common for fo long a period at 

 that feafon of the year in this part of America. But, by 

 one of thofe fudden tranfitions, which we often experience 

 here, on Thurfday evening, the weather became perfectly 

 clear, and continued the day following, as well as the day 

 of the Tranfit, in fuch a ftate of fcrcnity, fplendor of fun- 

 Ihine, and purity of atmofpherc, that not the leaft ap- 

 pearance of a cloud was to be feen. 



June 2d, and the forenoon of June 3d, were fpent in 

 making the neceflary preparations, fuch as examining and 

 marking the foci of our feveral telefcopes, particularly the 

 refledor, with and without the micrometer. The refledor 

 wasalfoplaced on a polar axis, and fuch fupports con- 

 trived for refting the ends of the refradors, as might give 



them a motion as nearly parallel to the equator as fuch 



hafty preparations would admit. Several diameters of the 

 Sun were taken, and the micrometer examined by fuch 

 other methods as the fhortnefs of the time would allow. 



The Sun was fo intenfely bright on the Day of the 

 Tranfit, that inftead of ufing the coloured glafles fent from 

 England with the Rcfledor, I put on a deeply-fmoakcd 

 glafs prepared by Mr. Liikcns, which gave a much more 

 beautiful, natural and well-defined appearance of the Sun*s 

 Di{k. The fmoaked glafs was fattened on the Eye Tube 

 with a little bees-wax, and there was no occafionto change 

 it during the whole day, as there was not the leaft cloud, 

 or intermiflion of the Sun*s fplendor. 



Mr. Rittenhoufey in his previous projedion (fee p. 4) 



E 



I 



5 



^ 

 i 



If 



S 





I 



r 



i 



for lat. 40"* N. and 



lono;. 



J' 



5^. W. of Greenwich: on 



II 



fuppoiition of the Sun's horizontal parallax being 8''. He 



happened 



