122 LECTURES 



This transit was also observed by Professor Winthrop, of Cambridge, 

 who had observed the previous transit in New Brunswick, and by Dr. 

 West of Providence. Observations were also made by the Earl of 

 Stirling, at Baskenridge, in New Jersey, and by Captain Holland near 

 Quebec. 



Several valuable papers, devoted to the record and discussion of 

 these observations, will be found in the transactions of the American 

 Philosophical Society for 1*769, and many in the transactions of the 

 Royal Society of London for 1769 and 1770. 



Professor Hornsby, of Oxford, who had computed the sun's parallax 

 from the observations of 1761, computed the same from five or six of 

 the best observations of 1769. But the most complete discussion of 

 the subject was by Lalande, who, by the close of the year 1769, had 

 collected a great number of observations, and discussed them in the 

 most elaborate manner. His results were published in the Gazette of 

 France, in January, 1770. 



In consequence of the unfavorable state of the weather only two of 

 the northern stations furnished full and complete observations, viz : 

 Wardhus and Cajanebourg. And, unfortunately, there was strong 

 reason to suspect that those at Wardhus, by Father Hell, were not 

 genuine. There was a delay and a reluctance in giving them to the 

 public, which much required explanation. And, after the fullest 

 investigation, there was reason to believe that some of them, at least, 

 were interpolations. 



The close agreements of the computed results of observations, most 

 widely separated, taken two and two, gave assurance of a close 

 approximation to the truth. The following were obtained by Lalande : 



California and Hudson Bay.. 8". 56 



Hudson Bay and Otaheite = 8", 55 



California and Otaheite 8". 53 



Wardhus, Cajanebourg, and Otaheite 8". 62 



The result of an immense amount of calculation by himself, Lexell, 

 Euber, Pingre, and Durejour, gave, 8". 5; 8". 7; 8". 8. In England, 

 Hornsby found 8". 8, Maskelyne 8", 7, Smith 8". 6. As a mean of all the 

 results, 8". 6 was adopted, which is the same as Short obtains from the 

 observations of 1761. The importance of arriving at the nearest tenth 

 of a second will be seen by considering that one-tenth of a second in 

 parallax corresponds to about 1,000,000 miles in the sun's distance. 



"Such," says Lalande, in closing his history of this astronomical 

 event, " such is the result of this celebrated transit of Venus, which 

 has occasioned so many voyages and so many volumes, and which has 

 taught us, much better than we knew before, the extent of our 

 universe, or at least of our solar system. This transit may be re- 

 garded as one of the memorable epochs of the astronomy of the 

 eighteenth century." 



But succeeding astronomers were far from being content to adopt, 

 without further inquiry, the foregoing conclusion. 



Encke, the eminent veteran astronomer of Berlin, has re-examined 

 and most elaborately collated and discussed all the observations made 

 at both the transits of 1761 and 1769, and given to the public the 

 results in two volumes, published, the one in 1822, the other in 1824. 



