222 THE NEW WORLD OF SCIENCE 



difference of time between Greenwich and Washington. In 

 that sense, therefore, America knew of the important events 

 of the war before the times at which they happened. 



Again, in the European campaign of 1815, which precipitated 

 the final downfall of Napoleon Bonaparte, the final battle took 

 place on the field of Waterloo. From the top of a tower 60 

 meters high on that field, the visitor is shown by his guide the 

 whole scene of tactical operations. On yonder elevation, the 

 French Emperor sat on his famous white horse, directing, by 

 couriers, the movements of his army. Over on this roadway, 

 Wellington rode up an/d down surveying the battle, and send- 

 ing verbal orders to his commanders. The battle opened early 

 in the afternoon, and the fate of the Napoleonic empire was 

 virtually sealed before darkness set in. 



Such was the nature of the last preceding great struggle in 

 Europe, when electrical communication did not exist, and when 

 the first, but unsuccessful experimental electric telegraph was 

 being tried, with frictional electricity, under discouraging con- 

 ditions, in the back garden of Sir Francis Ronald's house at 

 Hammersmith, in England. 



At the battle on the European western front in which the 

 A. E. F. participated in 1918, the American headquarters was 

 necessarily remote from the front line more than 200 kilo- 

 meters from some parts of it. The final battle lasted about four 

 months. Communication had to be constantly maintained by 

 the American headquarters, not only with each division com- 

 mander at the front, but also with the various reserves, depots 

 and bases, as well as with the Allied headquarters and with 

 the generalissimo in command of all the Allies. Moreover, 

 communication had to be maintained by each division head- 

 quarters, not only with its most distant outposts, through bri- 

 gade and regimental headquarters ; but also with its observation 

 balloons, its observation posts, airplanes and tanks. The army 

 was, therefore, extended over a vast network chain of electric 

 communications which ended, administratively speaking, in 

 Washington. Those links of the chains which cross the 



