THE CENTURY'S PROGRESS IN ASTRONOMY 



proved satisfactory, and, confident of the result, Leverrier 

 sent to the Berlin observatory, requesting that search be 

 made for the disturber of Uranus in a particular spot of 

 the heavens. Dr. Galle received the request September 

 23, 1846. That very night he turned his telescope to the 

 indicated region, and there, within a single degree of 

 the suggested spot, he sa\v a seeming star, invisible to 

 the unaided eye, which proved to be the long-sought 

 planet, henceforth to be known as Neptune. To the 

 average mind, which finds something altogether mysti- 

 fying about abstract mathematics, this was a feat 

 savoring of the miraculousr- 



Stimulated by this success, Leverrier calculated an 

 orbit for an interior planet from perturbations of Mer- 

 cury, but though prematurely christened Yulcan, this 

 hypothetical nurseling of the sun still haunts the realm 

 of the undiscovered, along with certain equally hypo- 

 thetical trans-Neptunian planets whose existence has 

 been suggested by "residual perturbations'' of Uranus, 

 and by the movements of comets. No other veritable 

 additions to the sun's planetary family have been made 

 in our century, beyond the finding of seven small moons, 

 which chiefly attest the advance in telescopic powers. 

 Of these, the tiny attendants of our Martian neighbor, 

 discovered by Professor Hall with the great Washington 

 refractor, are of greatest interest, because of their small 

 size and extremely rapid flight. One of them is poised 

 only 6000 miles from Mars, and whirls about him almost 

 four times as fast as he revolves, seeming thus, as viewed 

 by the Martian, to rise in the west and set in the east, and 

 making the month only one-fourth as long as the day. 



The discovery of the inner or crape ring of Saturn, 

 made simultaneously in 1850 by William C. Bond, at 

 D 49 



