592 



THE INDIA RUBBER WORLD 



1915. 



aked macaroni. These cords arc 

 .' inti a ingle compad - al 

 f or ,; Feet union, and then the plastu- ma 



the p wder press. 

 •[•|' u f orm of t r powder units is one of the technical 



art. because this regulates the speed with which 

 the grains will burn, and the uniformity with which they will 



rate their propulsive gases. Depending upon the sizi 

 t he gi > made, the "colloid" i ected to pre 



1 100 i 6,000 pounds to the squan inch, and undi i 

 lowerful piston the stuff is forced throu 

 di e that causes it to issue from the press in the shape of an 

 |i ss stick of pale yellow twisting and moving like a snake. 

 Instead of having on* hole, however, through its center, it has 

 that and a concentric group of others perforating the rod 

 from end to end. Every tunc the rod reaches the end of the 

 ,,,',', one "i the men cuts it off at the press outlet, and then 



tii, length is laid alongside its predecessors and straightened, 

 II,, , an next fed to a cutter, which divides the rods into the 

 died grains oi uniform length. The number of perforations 

 in the roils and the size of the grains are dependent upon the 

 caliber of the gun and the length of the weapon in which they 

 are to be fired. Here are details that should be explained. 



Ii the powder grains were solid it is clear that their outer sur- 

 faces would diminish as they burned and, accordingly, less and 

 less gas would be generated. Now the desire is really to main- 

 tain a reasonably uniform propulsive impulse up to a certain 

 point in the travel of the projectile after the shot has been set 

 in motion. Therefore, by means of the longitudinal perfora- 

 tions, the burning area is increased internally while the external 

 surface is diminished by the attacking flame. Thus a measure 

 of uniformity is secured, and the power back of the shell does 

 its work until the projectile has acquired its maximum velocity 

 during its journey to the rifle's muzzle. Therefore, the longer 

 the gun the bigger or longer the grain needful. 



Jt is not our purpose to go into the mechanical details of the 



We havi now seen how harmless cotton wasti an be trans- 

 formed into a smokeless propellent for guns, but a good deal 



remains ti ei before the powder is in a condition lor is- 



suance to the naval service. The same can be said , I the 

 smokeless powder manufactured bj the arm • P and 



Copyright 1915. R. < 



Powder Issuing from Press ox to Cutting Table. 



1. It is enough for us to know that 

 their piston rods must be held tight, and to that end thi 

 of rubber packing is employed. The same thing is required ai 

 pipe joints, and rubber lulling has many applications, Thi- is 

 especially so in plants where the solvent is made and also in the 

 acid house, where tin transforming chemical and its surphurous 

 acid are drawn off into carboys for carria ■ to the nitrating house. 

 The workmen in the acid house must also be safeguarded from 

 orn chemicals, and rubber gloves, rubber aprons and 



ire worn. 



Copyright I'M 5, R. G. Skerrett. 



In the Laboratory of a Powder Plant Rubber Has Many 



I'SES. 



is equally true of the explosive turned out at the numerous 

 plants now commercially engaged in this work. 



Finally, the powder is laid in shallow boxes or drawers in 

 the drying house, and these receptacles are maintained at fixed 

 temperatures. Gradually the powder grains darken and harden, 

 and in about six months from the day of forming the stuff is 

 ready to be submitted for ballistic testing, i. e., firing in guns 

 of the proper caliber, and the registering of the pressures de- 

 veloped. Every batch of powder is called a "lot." and no two 

 lots are exactly identical in their performances. In order to 

 secure the desired average of performance, powders of different 

 batches are mixed, and after testing the lot is given its "index." 

 In this way the ordnance experts know just how to apportion 

 the charge so that the propulsive effort of a succession of firings 

 will be substantially alike. 



Smokeless powder has revolutionized modern ordnance. For- 

 merly the gun was fashioned to measure its strength with the ex- 

 plosive violence of black powder. The designer knew that he 

 bad to use so much of it to get a desired propulsive effect, and 

 this explains the disproportionate bulkiness oi the rear part of 

 the older weapons around that portion of the bore in which the 

 propellent developed its maximum effort with amazing sudden- 

 n. ss. Today, on the other hand, the designer plans his gun 

 first, using his metal more skilfully, and distributing it in a way 

 that produces graceful tapering contours. Then, having 

 the physical characteristics of his weapon, he proceed- I 

 bis powder grains so that they will burn progressively to har- 

 monize with the construction of the rifle and the ultima'.', speed 

 to be given the shell at the instant it leaves the muzzle. Smoke- 

 lessness is an incident, and. as we have said, due to well nigh 

 perfect combustion. The primary purpose of the chemist was 

 to produce a propellent susceptible of the nicest control. 



The manufacture of explosives has been given such a tre- 

 mendous impetus in this country, a- well as across the water, 

 during the last six months, that it would be impossible to give 

 the present statistics of this industry with exactness, but they 

 .tin be approximated with considerable accuracy. At the time 

 of the taking of the last census — in 1910* — there were 6.274 work- 

 men employed in the No plants in the Uniti 5tal ted ti 



