ried in sections.

The Germans employ a mobile apparatus which is very similar, but in
this instance the mast is telescopic. When closed it occupies but little
space. By turning the winch handle the mast is extended, and can be
carried to any height up to a maximum of about 100 feet. The capacity
of these mobile stations varies within wide limits, the range of the
largest and most powerful installations being about 200 miles. The
disadvantage of these systems, however, is that they are condemned to
territories where the ground at the utmost is gently undulating, and
where there are roads on which four-wheeled vehicles can travel.

For operation in hilly districts, where only trails are to be found,
the Marconi Company, has perfected what may be described as "pack" and
"knapsack" installations respectively. In the first named the whole of
the installation is mounted upon the backs of four horses. The first
carries the generator set, the second the transmitting instruments, the
third the receiving equipment, and the fourth the detachable mast and
stays.

The generator is carried upon the horse's saddle, and is fitted with a
pair of legs on each side. On one side of the saddle is mounted a
small highspeed explosion motor, while on the opposite side, in axial
alignment with the motor, is a small dynamo. When it is desired to
erect the installation the saddle carrying this set is removed from the
horse's back and placed upon the ground, the legs acting as the support.
A length of shaft is then slipped into sockets at the inner ends of the
motor and dynamo shafts respectively, thus coupling them directly, while
the current is transmitted through a short length of flexible cable to
the instruments. The mast itself is made in lengths of about four feet,
which are slipped together in the manner of the sections of a fishing
rod, and erected, being supported by means of wire guys. In this manner
an antenna from 40 to 50 feet in height may be obtained.

The feature of this set is its compactness, the equal division of the
sections of the installation, and the celerity with which the station
may be set up and dismantled in extremely mountainous country such as
the Vosges, where it is even difficult for a pack-horse to climb to
commanding or suitable positions, there is still another set which has
been perfected by the Marconi Company. This is the "knapsack" set,
in which the whole of the installation, necessarily light, small,
a