If this become acute the vessel will be tilted,
rendering the position of the observers somewhat precarious, and
at the same time observing efficiency will be impaired.
This point may be appreciated more easily by reference to the
accompanying diagram. A represents the ground station and B
the position of the captive balloon when sent aloft in calm
weather, 300 feet of cable being paid out. A wind arises and
blows the vessel forward to the position C. At this point the
height of the craft in relation to the ground has been reduced,
and the reduction must increase proportionately as the strength
of the wind increases and forces the balloon still more towards
the ground. At the same time, owing to the tilt given to the
car, observation is rendered more difficult and eventually
becomes extremely dangerous.
A wind, if of appreciable strength, develops another and graver
danger. Greater strain will be imposed upon the cable, while if
the wind be gusty, there is the risk that the vessel will be torn
away from its anchoring rope and possibly lost. Thus it will be
seen that the effective utilisation of a captive balloon is
completely governed by meteorological conditions, and often it is
impossible to use it in weather which exercises but little
influence upon dirigibles or aeroplanes.
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