358 THE POPULAR SCIENCE MONTHLY. 



" I could wish," he says (I follow Ferguson's translation), " that many ob- 

 servations of the same phenomenon might be taken by different persons at sev- 

 eral places, both that we might arrive at a greater degree of certainty by their 

 agreement, and also lest any single observer should be deprived by the inter- 

 vention of clouds of a sight which I know not whether any man living in this 

 or the next age will ever see again, and on which depends the certain and ade- 

 quate solution of a problem the most noble, and at any other time not to be at- 

 tained to. I recommend it, therefore, again and again to those curious astrono- 

 mers who (when I am dead) will have an opportunity of observing these things, 

 that they would remember this my admonition, and diligently apply them- 

 selves with all their might to the making thi3 observation ; and I earnestly 

 wish them all imaginable success ; in the first place, that they may not, by the 

 unseasonable obscurity of a cloudy sky, be deprived of this most desirable sight ; 

 and then that, having ascertained with more exactness the magnitudes of the 

 planetary orbits, it may redound to their immortal fame and glory." 



A few years before the transit of 1761, Delisle, the French astrono- 

 mer, undertook a careful analysis of all the circumstances of the ap- 

 proaching phenomenon. It had been ascertained that the transit of 

 1761 was only the first of a pair of transits, the second occurring in 

 1769; and it was found that the method by which Halley had pro- 

 posed to utilize the earlier transit would not, on this occasion, be alto- 

 gether suitable. I shall presently describe the methods respectively 

 suggested, but it is necessary to mention them here, in order that the 

 chronological sequence of the events may be recognized. For many 

 who have heard Delisle's method lately spoken of and insisted upon 

 (as in Parliament by Mr. Goschen) have been led to imagine that it is 

 a recent invention, and, again, that it possesses great advantages over 

 Halley's, whereas it was known and discussed before the transits of 

 1761 and 1769, and, while very properly adopted for the first transit, 

 was as properly superseded by Halley's in the case of the second. 



The transit of 1761 (like that which will occur on December 6, 

 1882) was partially visible in England. It was observed at Green- 

 wich by the Rev. M. Bliss, Astronomer Royal, and at Savile House, 

 near London, by Mr. Short, " in presence," says the account, " of his 

 Royal Highness the Duke of York, accompanied by their Royal High- 

 nesses Prince William, Prince Henry, and Prince Frederick." A great 

 number of observations l were made also in different parts of the world, 

 and a sufficiently satisfactory determination of the sun's distance was 

 deduced therefrom. 



It was, however, in 1769, that the real attack was made. It was 

 then that the famous expedition of Captain Cook, in the Endeavor, 

 was made, England being the only country which had a station in the 

 Pacific. The arctic regions were visited also, a station being selected 

 at Wardhus, in North Lapland, where the following notable peculiar' 



1 There were 68 observing-stations in all, thus distributed : 13 in North Europe, 8 in 

 England, 15 in France, 6 in Spain, Portugal, and Italy, 16 in Germany, and 3 in other 

 places. 



