THE EXPOSITION SUMMER
of a millimetre (0*032 inch) in diameter, possess a high coefficient of rupture and a surface so slight that their substitution for the ordinary cord suspensions constitutes a greater progress than many a more showy device. Indeed, it has been calculated that the cord suspensions offered almost as much resistance to the air as did the balloon itself.
At the stern of this air-ship keel I again established my propeller. I had found no advantage result from placing it in front of the "No. 4," where it was an actual hindrance to the free working of the guide rope. The propeller was now driven by a new 12 horse-power four-cylinder motor without water jacket, through the intermediary of a long, hollow steel shaft. Placing this motor in the centre of the keel I balanced its weight by taking my position in my basket well to the front, while the guide rope hung suspended from a point still farther forward (Fig. 8). To it, some distance down its length, I fastened the end of a lighter cord run up to a pulley fixed in the after part of the keel, and thence to my basket, where I fastened it convenient to my hand. Thus I made the guide rope do the work of shifting weights. Imagine, for example, that going on
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