1,434 lb., and the disposable lift still remaining with crew of
two on board and full tanks, 659 lb.

The theoretical endurance at full speed as regards petrol
consumption is a little over 8 hours, but in practice it is
probable that the oil would run short before this time had been
reached. At cruising speed, running the engine at 1,250
revolutions, the consumption is at the rate of 3.6 gallons per
hour, which corresponds to an endurance of 16 1/2 hours.

With the engine running at 1,800 revolutions, a speed of 50.6
miles per hour has been reached by one of these ships, but
actually very few attained a greater speed than 40 miles per
hour.

The envelopes of S.S. airships are composed of rubber-proofed
fabric, two fabrics being used with rubber interposed between and
also on the inner or gas surface. To render them completely
gastight and as impervious to the action of the weather, sun,
etc., as possible, five coats of dope are applied externally, two
coats of Delta dope, two of aluminium dope and one of aluminium
varnish applied in that order.

One ripping panel is fitted, which is situated on the top of the
envelope towards the nose. It has a length of 14 feet 5 inches
and a breadth of about 8 inches. The actual fabric which has to
be torn away overlaps the edge of the opening on each side. This
overlap is sewn and taped on to the envelope and forms a seam as
strong and gastight as any other portion of the envelope. Stuck
on this fabric is a length of biased fabric 8 1/4 inches wide.