^ ^ /^. 



w^y t^-. 



ASTRONOMICAL PAPERS. 



27 







the Sun. But towards the internal contaBy the cuxular 

 border of light feemcd to grow more duiky towards the 

 points where the luminous fegments of the Sun*8 limb 

 were ready to clofc round the planet. This duflcinefs 

 did not feem to part wholly from the Sun's limb, at the 

 time lapprehended the body of Venus to be wholly entered 

 on the Sun, and when I gave the fignal for the internal 

 contad;, which was noted by both the perfons who coun- 

 ted for meat 2^. 28'. 5:8'' by the clock. And I judge at 

 leaft from iG'^ to 18'' more, before I faw the Sun's limb 

 clear of this dufky fliadow." 



SMITH 



OF THE Contacts. 



I 



L 



" The power kept on the Gregorian rejIcBor-^ for obfcr- 

 ving the conta^s^ as hath been already oblerved, was the 

 fame which we had been ufmg, and were again to ufe, 

 with the ymcromcter-i magnifying 95 times. 1 had therefore 

 a large field, taking in about half the Sun's difk; and the 

 inftrument was fo firmly fupportcd, with its axis in a po- 

 lar diredion, that it could not be fhaken by any motion on 

 the earthen floor of the obfcrvatory, and required only an 



eafy movement of one part of the rack- work to manage 

 it. With thcfe advantages, any part of the Sun's limb 

 could be readily kept in the middle of the field, without 

 negle£ling, every 4" or 5", to caft my eye on all other 

 parts of the limb on both fides, where there was any pof- 

 fibility of the contad ta happen. 



" Within half a minute of the time calcubircd for the id 

 contad by Mr. Rittenhoufe, I fpokc to the counters nt the 

 windows to be very attentive to thofe wlio were to give 

 them the fignals from the telefcopes out of doors; and 

 turning my eye clofcly to the part of the Sun's limb where 

 Venus was expcded, I had viewed it ficdfaflly for feveral 



to change my field, 

 when I was fuddenly furprized with fomcthing ilriking 



fcconds, without having occafion 



into it, like a watery pointed fliadow, appearing to give a 

 tremulous motion to all that part of the llrnb, aUhough 

 the telcfcope ftood quite firm, and not the leaft dillurbance 

 or undulation were perceptible about any other part. 



'' The 



i^ 



