200 Commetidatore G. Marconi [June 2, 



volt* when thai of the Ixittery or generators is li*.ut,»u. This poten- 

 tial is obtained in consequence of the rise of pnential at the con- 

 denser pktes, brought alx>ut by the rush of current through the 

 choking or inductance coils at each charge. These coils are placed 

 l>etween the battery or genen\tor and the condenser (•, Fig. 6. 



No practical difficulty has been encountered either at Clifden or 

 Glace Bay in regard to the insulation tmd maintenance of these high- 

 tension storage kitteries. Satisfactory insulation has been obtiiined 

 by dividing the k\ttery into small sets of cells placed on separate 

 stands. These stands are suspended on insulators attached to girders 

 fixed in the ceiUng of the k\ttery room. A system of switches. 

 which can all be operated electrically ;md simultaneously, divides the 

 battery into sections, the potential of each section being low enough 

 to enable the cells to be handled withoiu inconvenience or risk. 



The arrangement of aerial adopted at Clifden and Glace Bay is 

 shown in Fig. 7. This system, which is based on the result of tests 

 which I first described before the Eojal Society in June 1900.* not 



^ T 



Fig. 7. 



only makes it possible to efficiently radiate and receive waves of any 

 desired length, but it also tends to confine the main portion of the 

 radiation to any desired direction. The limitation of transmission 

 to one direction is not very sharply defined, but nevertheless the 

 results obtained are exceedingly useftil for practical working. 



In a similar manner, by means of these horizontal wires, it is 

 possible to define the bearing or direction of a sending station, and 

 also hniit the receptivity of the receiver to waves arriving from a 

 given direction. 



The commercial working of radiotelegraphy and the widespread 

 application of the system on shore and aflo;\t in nearly all pans of 

 the world, has greatly faciUtated the marshalling of facts and the 

 observation of effects. Miuiy of these, as I have already stated, still 

 a\\"ait a satisfactory explanation. 



A curious result which I first noticed over nine years ago in long 

 distance tests carried out on the S.S. "• Philadelphia." and which 

 still remains an important feature in long distance sjv^ce telegraphy, 

 is the detrimental effect productd by daylight on the propagation of 

 electric waves over great distances. 



* " On methods whereby the Radiation of Electric Waves may be mainly 

 confined, eic." Proc. Koy. Soc. , A. vol. lsx\"ii. , p. il3. 



