The cost of a loaded 75-millimeter shell with the fuse and propellant charge ready to be fired is about $11. Such a shell contains a little over 1½ pounds of high explosive, which costs $1. The loading and assembling of the complete round costs $4.
A loaded 155-millimeter shell complete with fuse costs about $30, exclusive of the propellant charge of powder, which is loaded separately. A shell of this caliber holds about 14¼ pounds of high explosive, which costs $10, while the loading and assembling costs $4.
The 75-millimeter and 155-millimeter shell were used in the greatest quantities on the European battle fields, and at the time of the signing of the armistice our American loading plants were concentrating on filling ammunition for guns of these two calibers.
The nature of the work carried on at these shell-loading plants, of course, made the danger of a disaster ever present. Prior to our entry into the war an explosion at the Canadian Car & Foundry Co.'s plant, Kingsland, N. J., resulted in the entire destruction of the plant with large loss of life.
In October, 1918, the Morgan plant of the T. A. Gillespie Co., South Amboy, N. J., was wiped out by an explosion in which about 100 employees lost their lives. Plans for rebuilding this plant, had progressed far when the armistice was signed. In the fall of 1917, 40 people were killed in an explosion at the Eddystone Loading Plant, Eddystone, Pa.
For the successful carrying out of our program for the production of vast quantities of explosives and propellants, as well as shell loading, the women of America must be given credit, on account of the highly important part they took in this phase of helping to win the war. Fully 50 per cent of the number of employees in our explosive plants were women, who braved the dangers connected with this line of work, to which they had been, of course, entirely unaccustomed, but whose perils were not unknown to them.
In connection with the production of shell themselves, the American Ordnance Department adopted certain changes of design which were not only radically different from what we had known before the war but were interesting for the way in which they were brought about and for the results they accomplished.
The modern shell as we knew it before the war was simply a metal cylinder cut off squarely at the base and roundly blunted at the nose. The shell is zoned with a so-called rotating ring, a circular band of copper which by engaging the rifling channels of the gun gives to the shell the whirl that keeps it from tumbling over and over and thus holds it accurately on its course in flight.
In the proof-firing of the 6-inch seacoast guns it was discovered that their fire was none too accurate; and the American ordnance engineers began studying the shell to see if the fault lay there. One of these experts was Maj. F. R. Moulton, who before accepting a commission in the Army had been professor of astronomy at the University of Chicago. Maj. Moulton began a study of the 6-inch shell; and soon it was discovered that the mathematics which could chart the orbits of comets could also deal with the flight of projectiles, calculate the influences of air resistance and gravitation, and eventually work out new, scientific contours for offsetting these influences as much as possible.