18 , ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Institution, have lately been published by it. The first record- 

 ed observation of Uranus was made by Flamstead in 1690, 

 who, however, considered the star as fixed. It was Sir William. 

 Herschel who, by the power of his telescopes, first saw its 

 planetary disk, and by its movements proved it to be really 

 a member of the solar system. The observed movements of 

 Uranus, however, differed to so great a degree from those 

 predicted by the theory of gravitation, that a certain mystery 

 hung about it until Le Verrier in France and Adams in En- 

 gland showed that the planet w^as subject to the attraction of 

 a more distant planetary body, whose position these geome- 

 ters predicted with sufiicient accuracy to allow of the actual 

 discovery of the new planet, Neptune. Professor Newcomb 

 has already, by using all known observations of Neptune, 

 compiled the very accurate tables for computing the motions 

 of that planet that have been used in the American Nautical 

 Almanac. Having thus provided for the most distant mem- 

 ber of our system, he has now returned to Uranus, and finds 

 that his present tables (which will comj^lete the survey of 

 the solar system) represent quite completeljr the hitherto in- 

 explicable movements of that body. There remains, there- 

 fore, but slight prospect that there exists a still more distant 

 undiscovered planet of any considerable mass. 



TELEGEAPHIC LONGITUDES IX SOUTH AMERICA. 



The use of electricity in determining geographical longi- 

 tudes keeps rapid pace with the continual extension of tele- 

 graph lines and cables over the w^orld. We lately chronicled 

 the third determination of the diiFerence of longitude be- 

 tween Washington and Greenwich, which datum, so highly 

 important to astronomy, may now be considered as known to 

 within the twentieth part of a second of time. The union of 

 London with Teheran, Persia, and through it with Madras, 

 India, was completed in the latter part of 1871, and a tele- 

 graphic circuit of 3870 miles of wire w^as used in the longi- 

 tude determination. The lono-itude of San Francisco from 

 Washington has been determined over a circuit of 3000 miles 

 by the astronomers of the Coast Survey. The net-work thus 

 gradually girdling the northern hemisphere now begins to be 

 supplemented b)^ the detached portions of what may at some 

 distant day become the connected links of a similar series of 



