Popular Science Monthly 



Ten tons of powder in 20-inch prisms 

 propel the shot, which encounters an atmos- 

 pheric resistance at the muzzle of 10.45 

 tons which fades off to zero at the first 

 point of impact. Ignition is reversed ; the 

 powder commences to burn at the shell's 

 base and works back to the breech-plug 

 so that the air is not filled with burning 

 powder grains, as is usually the case. 

 Fired point-blank the shell travels twenty- 

 one miles parallel with the earth's curva- 

 ture, which would permit the shot to 

 perforate two German fleets side by side. 

 At a 70-mile range the gun's possible de- 

 structive area is 15,386 square miles; at 

 the 100-mile range, 31,400 square miles. 



If this gun were using its 70-mile range 

 and it were located at Somerville, New 

 Jersey, it would command New York City, 

 Philadelphia, West Point, Mauch Chunk, 

 Wilmington, Delaware and all the inter- 

 vening country. One gun on the Panama 

 Canal would command both entrances with 

 deadly accuracy. 



The power required to operate the gun is 

 furnished by its own recoil. The rifle auto- 

 matically assumes the position for firing. 



The first part of 

 the recoil is ab- 

 sorbed by com- 

 pressed air cylin- 

 ders connected with 

 a series of glycerine 

 cylinders. At the 

 end of the recoil the 

 gun is locked in a 

 horizontal position 

 through compen- 

 sating gear and is 

 ready for automatic 

 cleaning and load- 

 ing, after which it 

 automatically ele- 

 vates itself and fires. 



845 



The gun is started and stopped by a foot 

 press. The elevation is recorded by a left- 

 hand wheel operating three dials — a degree 

 dial, a second dial and a minute dial, while 

 the point of compass is controlled by a 

 right-hand wheel with three other dials 

 geared for degrees, minutes and seconds. 

 Since harbors can be ruled off into imagina- 

 ry numbered squares, it is merely necessary 

 to telegraph the office in charge of the gun 

 that the hostile fleet is in square 22 or 64. 

 The operator places a pantographic pointer 

 on a metallic map at the position designated 

 and the gun does the rest. The area of each 

 square is coincident with the shell's own 

 destructive area, while the whole metallic 

 map is coincident with the gun's destruc- 

 tive area. 



The carriage weighs 98,492.5 tons with- 

 out the gun. It is practically an automo- 

 bile car resting on 250 soft iron wheels, 

 each of which is 2 feet wide and 2 feet in 

 diameter with 12 grooves in the rims for the 

 rope tires. 



Each wheel's bearings are a fork, like an 

 inverted "U," the handle being a plunger 

 terminating in a compressed-air cylinder. 

 All cylinders are 

 connected and sub- 

 ject to the same 

 pneumatic balance. 

 Each wheel may 

 be turned in any 

 direction by a gear 

 which connects all 

 wheels. Power is 

 transmitted to a 

 certain number 

 through double 

 cranks in a double 



If the largest cask you 

 ever saw were placed in 

 the mouth of the gun 

 it would probably look 

 as tiny as the one 

 shown here at the left 



In the drawing above 

 you get a fair idea of 

 the length of the bore 

 of the new gun. It 

 could accommodate an 

 engine and a train of 

 three usual-size cars 



An idea of the size of 

 the shell used is given 

 at left. An ordinary 

 eight-cylinder automo- 

 bile could be carried in 

 it and there would be 

 plenty of room to spare 



