HERTZIAN WAVE WIRELESS TELEGRAPHY. 155 



means of producing at least four hundred times the wave-energy that 

 had been previously employed. The author was therefore requested 

 to prepare plans and specifications for an electric generating plant 

 for this purpose, which would enable electrical oscillations to be set 

 up in an aerial on a scale never before accomplished. 



This work involved, not merely the ordinary experience of an elec- 

 trical engineer, but also the careful consideration of many new prob- 

 lems and the construction of devices not before used. Every step had 

 to be made secure by laboratory experiments before the responsibility 

 could be incurred of advising on the nature of the machinery and 

 appliances to be ordered. Many months in the year 1901 were thus occu- 

 pied by the author in making small scale experiments in London and 

 in superintendence of large scale experiments at the site of the first 

 power station at Poldhu, near Mullion, in Cornwall, before the plant 

 was erected and any attempt was made by Mr. Marconi to commence 

 actual telegraphic experiments. As this work was of a highly con- 

 fidential nature, it is obviously impossible to enter into the details of 

 the arrangements, either as made by the writer in the first instance, or 

 as they have been subsequently modified by Mr. Marconi. The design 

 of the aerial and of the oscillation transformers and many of the de- 

 tails in the working appliances are entirely due to Mr. Marconi, but as a 

 final result, a power plant was erected for the production of Hertzian 

 waves on a scale never before attempted. The utilization of 50 or 100 

 H.P. for electric wave production has involved dealing with many 

 difficult problems in electrical engineering, not so much in novelty of 

 general arrangement as in details. It will easily be understood that 

 Ley den jars, spark balls and oscillators, which are quite suitable for 

 use with an induction coil, would be destroyed immediately if employed 

 with a large alternating current plant and immensely powerful trans- 

 formers. 



In the initial experiments with this machinery and in its first work- 

 ing there was very considerable risk, owing to its novel and dangerous 

 nature ; but tliroughout the whole of the work from the very beginning, 

 no accident of any kind has taken place, so great have been the pre- 

 cautions taken. The only thing in the nature of a mishap was the 

 collapse of a ring of tall masts, erected in the first place to sustain 

 the aerial wires, but which have now been replaced by four substantial 

 timber towers, 215 feet in height, placed at the corners of a square 

 200 feet in length. These four towers sustain a conical arrangement 

 of insulated wires (see Fig. 26) which can be used in sections and 

 which constitute the transmitting radiator or receiver, as the case may 

 be. Each of these wires is 200 feet in length and formed of bare 

 stranded wire. t 



