WIRELESS TELEPHONY—SLAUGHTER. _ 191 
York and London is a comparatively simple matter, economic ques- 
tions have up to the present prevented serious consideration of such 
a project. It is entirely conceivable that improvements in the art - 
may soon bring the cost of such a system well within the limits im- 
posed by economic considerations. 
Wireless telephony between ships at sea or between a ship and a 
shore station is a logical supplement to the wireless telegraph service 
now furnished on practically all ocean-going steamships. In this 
case, as in the case of transoceanic telephony, economic considerations 
are apt to retard the extension of this field until the development of 
apparatus less expensive than present types. 
In the field of aviation, however, wireless telephony presents a 
number of advantages which it is believed will result in its rapid 
adaptation to the needs of this service. Entirely aside from the 
popular interest attached to telephone communication between dif- 
ferent airplanes, or between an airplane and a ground station, the 
practical value, particularly of the latter, is sufficient in many cases 
to justify the required expenditure to provide this facility. 
There are various special fields not included in the above which 
may call for the use of wireless telephony, such as communication 
between various islands of a group—for example, the Hawaiian 
Islands—the wireless telephone furnishing in this case trunk lines for 
tying together the telephone exchanges on the various islands. 
MILITARY FIELD. 
The use of wireless telephone apparatus in combatant military 
operations during the war was practically negligible. This should, 
however, not be interpreted as an indication that wireless telephony 
offers no advantages for military purposes, but rather that the 
training of personnel in its use had not proceeded sufficiently to 
warrant its use. Communications within various units of an army 
frequently call for extreme mobility of the apparatus. The pre- 
vailing method of establishing intermittent communication between 
temporary stations joined by wires laid on the ground is obviously 
far from ideal. If wireless telephone apparatus can be developed 
by means of which different centers of command can be kept in con- 
stant touch with each other while all are in motion the advantages of 
such communication will compel its adoption and wide use through- 
out the communication system of the Army. 
In naval operations the use of wireless telegraphy is so wide- 
spread that it forms an indispensable link in the naval communica- 
tions system. For certain kinds of service the advantages offered by 
telephony as compared with telegraphy make it extremely desirable 
that wireless telephone apparatus be developed to meet the require- 
