INCIDENTS IN THE DEVELOPMENT OF MOTORITE
Motorite consists of a compound of about seventy per cent. nitroglycerin and thirty per cent. gelatinated guncotton, the mixture being compounded in such a way as to form a tough and rubbery substance. This material is made into bars, which are smoothed and varnished upon the outside and then forced into steel tubes. In use, these steel tubes are placed in an apparatus in such wise that the bar of motorite can be ignited only at the exposed end, in a combustion chamber, into which water is forced, and as the combustion is confined to that end, it proceeds with absolute uniformity, according to the pressure, and without explosion. In other words, the motorite acts as a fuel, the products of combustion serving as a flame blast, blowing the water through a series of baffle plates, atomizing it, and converting it instantly into steam. The object of motorite is to replace compressed air in the driving of motors for self-propelled torpedoes.
I have already expended more than fifty thousand dollars in experiments with motorite and on different kinds of apparatus for its use. As about four times as much energy is available for driving a torpedo by this system as by any other, I hope some time to effect arrangements for the equipment of torpedoes with it.
The first bars of motorite that I made, I formed by passing through a die. The result was that a small, microscopic flaw which could not be seen with the naked eye extended through the bars from end to end, so that, when the bar was placed in the combustion apparatus, the flame of ignition passed immediately down through the flaw, exploding the apparatus.
After the first apparatus blew up, I made another one, and, as I could not very well conduct the experiments at the place where the first mishap occurred, I hired a floor in a building to make the test. But I needed an assistant, and it was problematical where I could find one.
One day, while returning home, I was accosted by a panhandler, a young man claiming to have just arrived from Pittsburg, seeking work. I told him that if he was actually looking for work I had a job for him, and I bade him come right along with me. I took him home that night, fed him, and watched him.
The next morning we went down to the shop. I explained to him all about the nature of the experiment that I was about to try, and told him that, if he had any timidity, the time to abscond was then and there. He told me that he was not afraid of anything, if I was not.
“Very well, then,” I said, “I do not expect the thing to blow up; otherwise, I would not be here.”
I got my time-watch ready, and told him to press the electric button to ignite the motorite. Instantly there was a terrific explosion. The windows were blown out into the street, and pieces of the shattered apparatus were driven into the ceiling and into the wall all about us; but fortunately neither of us was hit.
John looked calmly about him for a moment, and then at me, and remarked:
“God, she busted!”
While we were recovering from our amazement, half a dozen policemen rushed into the place, accompanied by a priest. I explained the mishap the best way I could, and, seeing that the priest was a handsome, genial, good-natured fellow, I appealed to him. He had a little chat with the policemen, and they all left.
I sent that priest a box of the best cigars that I could buy.
Under the counsel and advice of the landlord I then moved away from there.
I next bought a house, and in the back yard I built a laboratory with no windows or doors in it, except a skylight at the top and the windows and doors that fronted my house. The walls were of brick, and made thick. The skylight at the top was a large one, and was arranged to open up full size. Special precautions were taken by means of various attachments to cause the roof to stay on in case of emergency.
A new apparatus was made and erected and got ready to test. This time my wife was my assistant, and we arranged to touch the thing off by electricity from the house. Again it exploded, and one of the fragments of the apparatus, coming through the open door, struck the wooden wall behind which my wife and I were standing and nearly passed through it.
On entering the laboratory, I discovered for the first time what was the actual cause of the trouble, namely, the longitudinal flaw already referred to, evidenced by the fragments of the motorite that remained after the explosion, for motorite, like smokeless gunpowder, when subjected to explosive pressure, is immediately extinguished upon the release of the pressure, so that when the apparatus blew up, all of the unconsumed motorite was extinguished, just as when the projectile leaves the gun any unburned smokeless powder is extinguished and is blown out in front of the gun, where the partially consumed grains may be recovered.
The next motorite was made by rolling the material into sheets, cutting into discs, sealing them together under pressure, and in that way building up the bars, which precluded the possibility of there being any flaws.
Some motorite was soon made in this manner, and another apparatus constructed, which was tested and which worked very satisfactorily.
Following this successful result, I built a laboratory at a dynamite plant near Lake Hopatcong for conducting the experiments on a larger scale.
My assistant at the motorite laboratory was one of that American country type, absolutely honest, perfectly fearless, painstaking and diligent, of such timber as the great men of the earth are made. He was altogether a most lovable fellow. He had all his life worked with explosives, and was a veteran in the manufacture and use of nitroglycerin and dynamite. But, when doing pioneer work with explosives, there is always an unavoidable element of risk, even when the greatest care is taken.
We at first had the hydraulic press, in which we built up the sticks of motorite, located in the laboratory room itself; but I suggested to my assistant one day that it had better be placed outside, and a heavy brick wall built between us and the press, as a barricade in case of a possible accident.
“For,” I said, “suppose you should by oversight neglect to put in the leather packing between the piston and the motorite, we might have an explosion.”
He said that he could hardly forget that precaution. Nevertheless, the press was placed outside, and the barricade built. The very first time that we used the press thereafter he did forget the packing, with the result that the press exploded. Although we were behind the barricade, still the concussion brought us to our knees. Had the explosion occurred while the press was being operated in the main laboratory, we should both have certainly been very seriously injured, if not killed.
It was a matter of several months before the full-sized torpedo apparatus with which we were to experiment was completed and erected, and the necessary quantity of motorite made.
On the day before the regular test was to be conducted, I was called to Morristown, as expert on a case in court, and I left orders with my assistant to make up an additional small quantity of sealing compound, used for sealing the discs of motorite together in building up the bars. This sealing material was made of a mixture of nitroglycerin, guncotton, camphor and acetate of amyl.
As I did not receive the telegram to go to Morristown until after I left home that morning, my wife expected that I would be working at the laboratory that day, but knew that I might possibly have a call to Morristown.
On my way home that evening, I was informed by a neighbor that there had been an explosion in my laboratory, that my assistant had been killed, and that the place had been burned down. I hastened to the spot and found my wife there waiting for me. All that was left of my assistant lay in an adjacent building covered with a piece of sacking.
That was one of the saddest moments of my whole life. It is impossible to know what little slip or misjudgment may have produced the explosion. A little inadvertence in the handling of a bottle of nitroglycerin may have been the cause.
The manner in which my wife was informed of the accident was about on a par with that employed by the Irishman who took the remains of a fellow-workman, killed by an explosion, home to his wife in a wheelbarrow, and, knocking upon the door, asked:
“Does the widdy McGinnis live here?”
She replied: “Indade, and I’m not a widdy.”
And he said: “And faith ye are, for I have his rimnants here in the wheelbarry with me.”
A butcher was the messenger-bearer to Mrs. Maxim. He said:
“Mrs. Maxim, have you heard the news about the explosion?”
And he continued: “Mr. Maxim’s laboratory blew up and burned down today. They have found some of his assistant, but they haven’t found any of Mr. Maxim yet.”
Mrs. Maxim immediately rushed to the scene of the accident, where she learned the welcome news that I was in Morristown that day.
It was a matter of another year of hard work before I was again ready to make a new trial of the torpedo apparatus. There were several amusing experiences in connection with that testing.
The apparatus held a charge of one hundred and ten pounds of motorite. Water was pumped continuously through a water jacket over the steel cylinders containing the burning motorite and into the combustion chamber during each run. The apparatus was provided with an exhaust valve so constructed as to control, to a nicety, the pressure in the combustion chamber.
Under three hundred pounds pressure to the square inch, which was what was mainly used, the motorite burned at the rate of a foot in length per minute, and as each foot in length weighed twenty-five pounds, it burned at the rate of twenty-five pounds per minute. Each pound of motorite evaporated a little more than two pounds of water, and the products of combustion, mingling with the steam produced, escaped from the exhaust valve through an inch-and-a-half nozzle.
The roar of the escaping gas and steam was so great that it was impossible to hear one shout at the top of his voice. The loudest shout was less than a whisper. The roar could be heard with great distinctness more than two miles away. A good idea can be had of the violence with which the steam and gases escaped, from the fact that a door, which accidentally swung shut during one of the runs in front of the nozzle, although seven feet distant, was blown from its hinges, broken in two, and the fragments hurled twenty feet away. The noise was so confounding, that it was some time before my assistants and myself could keep our senses about us and note and record the pressures on the various gauges during a run, although the apparatus was separated from us by a barricade so strong and heavy that there was no possibility of our being injured, even should there be an explosion.
One day, just as we were about to make a run, the superintendent of a nearby explosives works called upon us, and I asked him if he would like to see the run, and he said he would.
I then asked him to note particularly and to record the pressure on a certain gauge. The run lasted about five minutes and, on turning to him for his notes, he himself was surprised that he had been so confounded by the noise that he had not thought of looking at the gauge at all.
On the day when the final test took place, the firm of torpedo-builders that was interested with me in the apparatus sent several representatives, including their chief engineer, vice-president and other officers of the company, to witness the test. Everything being in readiness, and each member of the committee being convinced that there was no possible danger in remaining in proximity to the apparatus and back of the barricade, while it was being tested, I gave each of the committee explicit instructions to watch the various gauges and to note the pressures, while the chief engineer and myself were to watch the nozzle gauge, and to observe the character and force of the steam and gases escaping from the nozzle.
I told the several members of the committee it was indispensable that they should carefully watch the pressure gauges during the entire run. As it was a condition of the test that I should get up steam within ten seconds, the chief engineer stood ready with his stop-watch when the electric button was pressed to ignite the motorite.
As the action was instantaneous, that is to say, as steam was got up practically instantaneously and was escaping at the nozzle under full head as quickly as a gun could be fired, he did not think of his stop-watch, and it was some little time before I could get him to look at the pressure gauge on the nozzle, so as to observe the character of the escaping steam. His eyes had a blank, meaningless look, but it must be confessed that he had the grit to stand there. Not so, however, with the other members of the committee. Each of them was far more interested in his own individual run than he was in the run of the apparatus, for not one of them was in sight when the run was completed. They came straggling back sheepishly, but no urging sufficed to bring them near the apparatus during any of the succeeding runs.