MILITARY AERONAUTICS SQUIER. 125 



Stability. — This is nuiintained entirely by the cylinders at the rear. 

 Counting the larger one to which the smaller ones are attached, 

 there are five, arranged side by side corresponding to the liorizontal 

 planes of the Patrie, and five vertical ones corresponding to the 

 Patrie's vertical planes. The volume of the small cylinders is so 

 calculated that the gas in them is just sufficient to lift their weight, 

 so they neither increase or decrease the ascensional force of the whole. 

 The horizontal projection of these cylinders is 1,076 square feet. The 

 center of this projection is 72 feet from the center of gravity of the 

 gas. The great objection to this method of obtaining stability is 

 the air resistfyice due to these cylinders, and consequent loss of speed. 

 The stability of the Ville de Paris in a vertical plane is said to be 

 superior to that of the Patrie, due to the fact that the stability planes 

 of the latter do not ahvays remain rigid. The independent velocitj' 

 of the Ville de Paris probably never exceeded 25 miles an hour. 



Rudder. — The rudder has a double surface of 150 square feet 

 placed at the rear end of the car, 72 feet from the center of gravity. 

 It is not balanced, but is inclined slightly to the rear so that its 

 weight would make it point directly to the rear if the steering gear 

 should break. Two pairs of movable horizontal planes, one at the 

 rear of the car having 43 square feet, and one at the center of gravity 

 (as on the Patrie) having 86 square feet, serve to drive the airship 

 up or down without losing gas or ballast. 



Guide ropes. — A 400-foot guide rope is attached at the front end 

 of the car. A 230-foot guide rope is attached to the car at the center 

 of gravity. 



About thirty men are reciuired to maneuver the Ville de Paris on 

 the ground. The pilot has three steering wheels, one for the rudder 

 and two for the movable horizontal planes. The instruments used 

 are an aneroid barometer, a registering barometer giving heights up 

 to 1,600 feet, and an ordinary dynamometer which can be connected 

 either with the gas bag or ballonet by turning a valve. A double 

 column of water is also connected to the tube to act as a check on 

 the dynamometer.' Due to the vibration of the car caused by the 

 motor, these instruments are suspended by rubber attachments. 

 Even with this arrangement it is necessary to steady the aneroid 

 barometer wnth the hand in order to read it. The vibration prevents 

 the use of the statoscope. 



England. 



Military Dirigible No. 1. 



The gas bag of this airship was built about five years ago by 

 Colonel Templar, formerly in command of the aeronautical establish- 

 ment at Aldershot. His successor. Colonel Capper, built the me- 



