A. MATHEMATICS AND ASTRONOMY. .. 17 



that the exact time is thence daily distributed by electricity 

 over some thousand miles of main and branch roads by a 

 purely automatic process. For technical details the article 

 cited may be referred to ; and we briefly state that continu- 

 ous lines of telegraph, which extend from New York on the 

 east, and Chicago on the west, are carried into the observa- 

 tory, at Pittsburgh, where the wires terminate in its principal 

 mean-time standard clock, which is made to send an electric 

 impulse through them with every swing of its pendulum. 

 An audible sound is thus made simultaneously at every sta- 

 tion on the Southern lines connecting New York with the 

 West, and a clock regulated with astronomical exactness is 

 thus virtually to be heard ticking in JSTew York and Chicago, 

 and at hundreds of intermediate points, at the same instant. 

 The means employed are here alluded to, however, less in 

 connection with the abstract interest of the method itself 

 than to that of the practical and economical results which 

 are secured by such uniformity and exactness, hitherto gen- 

 erally unattained. Among the competing lines for the im- 

 mense amount of railway freight which passes between the 

 East and West, those which can be run with a regularity 

 most like clock-work will be the fovored ones ; but this es- 

 sential benefit, growing out of such a system of time distri- 

 bution, is still second to its utility as a security against ac- 

 cident, and for the preservation of human life. 



The special apparatus of the observatory devoted to these 

 ends is the gift of W. Shaw, Esq., of Pittsburgh ; but a recog- 

 nition is due to the intelligent policy which has led the man- 

 agers of these roads to avail themselves of scientific help so 

 extensively in promoting both the safety of passengers and 

 the rapidity and economy of transportation. 



NEW OBSERVATORY AT TASHKEND. 



An astronomical and meteorological observatory is about 

 to be erected by the Russian government at Tashkend, in 

 Central Asia, about 100 miles northwest of Khokan. 12 A^ 

 Novemher 25, 1872, 71. 



NEW TABLES OF URANUS. 



Professor Newcomb's New Tables of the Motions of Ura- 

 miSy which were prepared at the expense of the Smithsonian 



