1879.] 



On the Transit of Venus. 



301 



Contact. 



Hennessey. 



James. 



Time. 



Interval from 

 1st. 



Time. 



is <A 



Interval from 

 1st. 



1st Internal . . 

 2nd 



2nd External 



h. m. s. 

 14 17 9 

 18 5 33 

 18 32 50 



h. m. s. 



3 48 24 



4 15 41 



h. m. s. 

 7 41 20 

 11 30 15 

 11 57 25 



b. m. s. 



3 48 36* 



4 15 44* 



Mr. James was not in a position to obtain absolute time with, any 

 great accuracy, but this does not vitiate his intervals. There is every 

 reason to accept these as accurate, for Mr. James was quite familiar 

 with the telescope, which was his own property, and was accustomed 

 to study celestial objects. The accordance of these intervals (by 12 

 seconds and 3 seconds) is sufficient proof, apart from needless reduc- 

 tion, that if a contact-blunder of three minutes was committed in my 

 first time, about the same occurred in Mr. James's. This, as a blunder, 

 is, to say the least, highly improbable. 



6. I think, therefore, it may be claimed for both Mr. James and 

 myself that neither of us committed any blunder, as such, whether of 

 record or contact. On the other hand, I confess my inability, at 

 present, to account for the anomaly. 



7. Turning briefly to the preceding observatory notes, it will be seen 

 that, for purposes of emphasizing the visible absence of the expected 

 ligament, I roughly estimated the intervals from 2nd internal contact 

 (when the ligament was intently looked for) on five occasions in terms 

 of Venus' diameter ; thus, ^th to ^th diameter. If, for purposes of 

 very rough comparison, we contrast these roughly estimated fractional 

 diameter-intervals, with corresponding fractions of the observed 

 interval between 2nd internal and 2nd external contacts, there result as 

 errors in the former : 



Error of ^th diameter +68 seconds, 

 ith „ + 46 „ 

 55 |th ,, +52 „ 

 ,•> tV^ 55 —27 ,, 



55 2" 1 0^ n 55 25 ,, 



which is confirmatory to some extent of the absence of gross error in 

 the times of these two contacts. 



Mr. James's letters to me in original is attached. 



Excerpt from Mr. H. D. James's letter, above referred, to. 



" Chakatra, KW.P., December 9, J 874. 

 " Through your kindness in sending me a diagram of the planet's 

 * Intervals corrected for watch rate, giving " perhaps a minute in 12 bours." 



