i8o THE POPULAR SCIENCE MONTHLY. 



Some similar system should be adopted by railways leading out of 

 New York, whose standard clocks could be connected at a trifling 

 expense with the main clock, and kept right to within less than thirty 

 seconds, which is near enough for most purposes. It should not be 

 forgotten that each clock so controlled has the same accuracy as if 

 it were directly controlled by the standard astronomical clock of 

 the Naval Observatory at Washington, since the time which is ob- 

 tained at that institution is directly distributed throughout the system. 



For railways this system is peculiai'ly advantageous. Most rail- 

 ways adopt the time of one city as the standard time, by which all 

 trains are run, and to which the watches of all employes are adjusted. 



Suppose this should not be New York time, but another, as Pough- 

 keepsie time, for example. A simple device, lately proposed by an 

 inofenious writer in the New York Tribune, enables the New York 

 clock to be controlled to both times. This consists of a double min- 

 ute-hand that is, instead of making a single minute-hand, make it 

 double, with two pointers, so that when one points to New York 

 time, the other points to Poughkeepsie lime. The controlling stop, 

 or pin, acts upon the New York minute-hand, but the other hand ia 

 equally kept right. 



Such a clock will serve to conti'ol in its turn all the clocks along 

 the line of the railway by a daily signal, so that at every railway-sta- 

 tion the station-master's clock indicates, say, Poughkeepsie time. If 

 required for the benefit of the citizens of each place, a second minute- 

 hand can be added to each of these secondary clocks, so that the local 

 time of each station can be indicated, while at the same time each 

 railway-clock affords the means to each railway-employe of correcting 

 his own watch. This system, so simple in theory, is equally simple 

 in practice, and requires nothing but the care and fidelity of the agents 

 to whom its execution is confided to make it eminently useful and 

 beneficial. It should be remembered, however, that to carry out its 

 pi'ovisions carelessly is to commit a positive crime, since so much 

 depends upon its results. Similar systems of control are now provided 

 in many places. The observatory at Washington controls several 

 clocks in the various departments; and in London, Edinburgh, Paris, 

 Vienna, Bern, and elsewhere, this work is successfully carried on. 



The distribution of time-signals (either with or without controlled 

 clocks) to railways, etc., is a most important matter, in which the 

 United States is far behind England, for example, where about five 

 hundred railway-stations receive a signal daily. This is partly due 

 to the enormous extent of America in longitude, so that very different 

 local times are used at different places of the same continuous railway- 

 line, and partly to the fact that the telegraphs are owned by the Gov- 

 ernment in England, thus rendering the execution of a general system 

 of time-signals comparatively easy. In the opinion of many experi- 

 enced and prominent railway-officials in the United States, it is quite 



