So THE POPULAR SCIENCE MONTHLY. 



made. It was indeed the prevalent idea in Europe that that would be 

 the course she would adopt. But, with singular generosity and scien- 

 tific zeal, she not only devoted to the work of observing the earlier 

 transit a sum largely exceeding the amount granted by any other gov- 

 ernment (and nearly twice as large as Great Britain j>aid), but under- 

 took some of the most difficult portions of the work, which otherwise 

 would have been left unprovided for. I cannot but recall with a feel- 

 ing of something like personal satisfaction (though conscious that 

 such a feeling ought to find no place in the mind of the true student 

 of science), the gratification with which I welcomed the announce- 

 ment, early in 1873, that America had undertaken to occupy positions, 

 the importance of which I had long pointed out, but which, but a 

 fortnight before that announcement reached Europe, had been confi- 

 dently described as astronomically inferior and geographically unsuit- 

 able. The pleasure I then felt was only surpassed by that w r hich I 

 experienced subsequently, w r hen news received from the various ob- 

 serving stations showed that at those just mentioned were achieved 

 some of the most important successes of the occasion. 



Another noble contribution made to science at Washington has 

 been the erection of the splendid refractor 26 inches in aperture, 

 which is now the chief equatorial of the observatory. America is for- 

 tunate in possessing in Alvan Clark the greatest living master of the 

 art of constructing large object-glasses of good definition. He had 

 already constructed a telescope 18 inches in aperture for the observa- 

 tory at Chicago, but by the contract negotiated with him in August, 

 1870, by Prof. Newcomb, he was called on to achieve a far more diffi- 

 cult task in the construction of a telescope of 26 inches clear aperture. 

 He has successfully accomplished this task, and the telescope has 

 already obtained good results under Newcomb's skillful management. 

 The most important of these is an extensive series of observations of 

 the satellites of Uranus and Neptune, made with a view of determin- 

 ing the elements of their orbits and the masses of the planets round 

 which they circle. The observation of the two Uranian satellites, 

 Ariel and Umbriel, discovered by Lassell, and of the Neptunian satel- 

 lite also discovered by him, must be regarded, on account of the ex- 

 treme difficulty of observing these bodies, as a very valuable contri- 

 bution to astronomy. It is pleasant to notice that Newcomb has been 

 able most thoroughly to confirm the accuracy of Lassell's work in Mal- 

 ta, the mean motions of Ariel and Umbriel deduced from the Malta 

 observations being so accurate that, says Newcomb, " they will prob- 

 ably suffice for the identification of those objects during several cen- 

 turies." Although no systematic search has been made for new sat- 

 ellites of Uranus, yet enough has been done to show, "with consider- 

 able certainty," that at least the outer satellites supposed to have 

 been seen by Sir W. Herschel " can have had no real existence " (as 

 satellites, that is to say). 



