RADIOTELEGRAPH Y—MARCONI. 129 
attached. It therefore would seem that wireless telegraphy as at 
present practiced is, to some extent at least, dependent on the con- 
ductivity of the earth, and that the difference in operation across 
long distances of sea compared to over land is sufficiently explained 
by the fact that sea water is a much better conductor than is land. 
The importance or utility of the earth connection has been some- 
times questioned, but in my opinion no practical system of wireless 
telegraphy exists where the instruments are not in some manner con- 
nected to earth. By connection to earth I do not necessarily mean 
an ordinary metallic connection as used for wire telegraphs. The 
earth wire may have a condenser in series with it, or it may be con- 
nected to what is really equivalent, a capacity area placed close to 
the surface of the ground. It is now perfectly well known that a 
condenser, if large enough, does not prevent the passage of high- 
frequency oscillations, and therefore in this case, when a so-called 
balancing capacity is used, the antenna is for all practical purposes 
connected to earth. 
I am also of opinion that there is absolutely no foundation in the 
statement which has recently been repeated to the effect that an earth 
connection is detrimental to good tuning, provided of course that 
the earth is good. 
Certainly, in consequence of its resistance, what electricians call a 
bad earth will damp out the oscillations, and in that way make tuning 
difficult; but no such effect is noticed when employing an efficient 
earth connection. 
In conclusion, I believe that I am not any too bold when I say that 
wireless telegraphy is tending to revolutionize our means of communi- 
cation from place to place on the earth’s surface. For example, com- 
mercial messages containing a total of 812,200 words were sent and 
received between Clifden and Glace Bay from May 1, 1910, to the 
end of April, 1911; wireless telegraphy has already furnished means 
of communication between ships and the shore where communication, 
was before practically impossible. The fact that a system of imperial 
wireless telegraphy is to be discussed by the imperial conference, 
now holding its meetings in London, shows the supremely important 
position which radiotelegraphy over long distances has assumed in 
the short space of one decade. Its importance from a commercial, 
naval, and military point of view has increased very greatly during the 
last few years as a consequence of the innumerable stations which 
have been erected, or are now in course of construction, on various 
coasts, in inland regions, and on board ships in all parts of the world. 
Notwithstanding this multiplicity of stations and their almost con- 
stant operation, I can say from practical experience that mutual 
interference between properly equipped and efficiently tuned instru- 
38734°—sm 1911——9 
