*British Astra-Torres.* A number of comparatively small Astra-Torres dirigibles have also been built in Great Britain for coast patrol and anti-submarine work. The line drawing at the left of Fig. 21 illustrates the general design and construction of these small airships, while the various letters indicate the different parts of the gas container, air balloonets, suspension and car, and the end view at the right of the figure shows the small amount of head resistance offered by the suspension of this type as compared with that of the usual form of nonrigid dirigible. _A_ is the balloon itself, or main gas container, the pressure relief valve for which is located at _M_. _BB_ are the air balloonets connected with the blower _H_ in the car. In the illustration these balloonets are shown fully inflated as they would be after the gas bag had lost a considerable proportion of its original contents through leakage or expansion. At the beginning of a flight, when the gas bag is fully inflated with hydrogen, they lie perfectly flat along the lower side of the envelope, being brought into service only as they are needed to keep the envelope distended to its full volume. The novel method of suspension to which this type of dirigible owes its greater speed and fuel economy, because of the reduction of the head resistance, is shown by the numerous supporting ropes _O-O-O_, which terminate in a comparatively few cables attached to the car. In the small British airships referred to here, there is but one small car designed to carry a crew of two men and the engine is of comparatively low power, driving a propeller at either end of the car, but in the large French dirigibles of the same type, two large cars are placed tandem some distance apart and are fitted with 500-horsepower motors. The various parts indicated by the letters are: _CC_ propellers, _D_ motor, _F_ space for pilot and crew, _G_ fuel and oil tanks, _J_ guide rope, _K_ gas valve, _LL_ air valves, _NN_ balloonet cable, _P_ rudder, _Q_ stabilizer, _RR_ bracing cables, and _S_ the car itself. MILITARY USES OF ZEPPELINS