Electricity in Warfare

SUGGESTIONS THAT HAVE ARISEN FROM RECENT EXPERIMENTS.

An Electrician Thinks it May be Possible to Damage a Ship by Sending an Intense Current from the Shore or a Float.

When Nikola Tesla invited some of his associate members of the American Institute of Electrical Engineers and members also of the Electric Club to witness some experiments recently the invitations were accepted most eagerly. Some intimation of a discovery by Mr. Tesla of a new phase of electricity had crept out. Tesla’s repute as an electrician justified the highest expectations, and led electricians to wonder whether the strange things which he had discovered or developed might not be the beginning of another stage of progress in the application of electricity to commercial pursuits.

The experiments have been noted with great interest by the electrical journals and by scientific men. Mr. Tesla used a dynamo which produced electric waves of a peculiar character, immense rapidity, and enormous voltage. The current from the dynamo was led to two metal plates, so placed that one was on either side of the lecture room walls, and they were directly opposite each other. When the current was turned on it was discovered that the electric waves generated by the dynamo were carried or propagated through the air of the room from one plate to the other, and without any communicating medium visible to the eye, such as a wire. Extraordinary results were produced which fascinated the spectators. They were witnessing something new, startling, perhaps almost appalling in its suggestive possibilities. When Mr. Tesla held in his hand the carbon filaments of an electric lamp so that a line drawn from one of the plates to the other would pass through the lamp, very brilliant incandescence was produced. No metallic substance whatever connected the lamp with the plates. When he withdrew the lamp, so that it was no longer within range between the two plates, the light was extinguished instantly.

Of course, that demonstration revealed to the electricians that it was possible to convey an electric current from one plate to another and with such intensity as to produce a most brilliant electric light in an incandescent lamp through the medium of the air. Another experiment demonstrated that if a man stood within range of this electric current his body became instantly so heated that the warmth of it was perceptible. It was suggested that if a current of sufficient intensity should pass between the plates it would pass through the body of a man, and might wither or scorch him, but an experiment in that direction has not been made the subject of discussion.

One of the members of the Institute, Mr. J. J. Carty, was impressed by the experiments, for they suggested to him certain ideas which had occurred to him in the course of his examination and study of the uses of electricity as applied to commercial development. As the executive head of the mechanical and scientific department of the Metropolitan Telephone Company, he is recognized as an expert in practical matters, as well as an authority in some of the most advanced questions of electrical research. In the early fall, when trouble seemed to be brewing with Chili, and later on when war was deemed to be imminent, Mr. Carty gave such time as he could spare from his duties to the consideration, in a purely technical way, of the probability of the application of electricity to the uses of warfare, and especially to the realm of possibilities which Tesla’s experiments seem to open. A day or two ago Mr. Carty, having some leisure, spent an hour or two in discussing these matters, and while he said that the suggestions which he made might be of no immediate practical value, yet they were suggestions which scientific electricians might not despise, while, if they were set forth in language which laymen can understand, they might prove of popular interest in view of the fascination which the study of electricity seems to have for the masses.

In beginning Mr. Carty said that when the war of the rebellion opened, our navy was composed of wooden ships, and that there was a bigger gap between these ships and the little cheese box which made successful defence against the Merrimac in Hampton Roads than there is between the present methods of warfare and the revolution which may be made possible by electrical science in the manner of conducting it. The Monitor was the outcome of necessity. Probably we could have relied on the present methods of warfare had there been a contest with Chili, yet in a prolonged struggle with a nation as powerful as we are we should probably have cast about for some new methods of attack and defence, and, of course, would have turned to electricity to solve the problem.

“Now,” Mr. Carty said, warming to the subject, “what can electricity do for warfare? Everybody knows that it is doing something now, but its use is purely conventional. It furnishes motive power for training guns and working light machinery, for exploding mines and torpedoes, for signalling, and for the search light.”

“Is not the search light an aid for attack?”

“Hardly that, but in the search light we may find the germs of a future engine of war perhaps as revolutionary as was the Monitor. Already it may be utilized to interfere with the vision, and even in peace we see how powerfully it can do that, for we remember how bitterly the pilots complained of the light at Hell Gate, so bitterly, in fact, that it was taken down. Now, every schoolboy knows that Archimedes was said to have destroyed the fleet of the Romans before Syracuse by using burning mirrors. The energy thrown out by a search light cannot be made sufficient to do that, yet it suggests certain possibilities, taken in connection with the remarkable experiments of Mr. Tesla. In this experiment, which has already been described to you, Tesla followed out the latest conception as to the nature of electricity, which is that electricity, in many of its phases, is a form of vibration in the ether quite analogous to the vibrations of light and heat. This theory has been demonstrated lately by a wonderful series of experiments conducted by Hertz in Germany, and the experiments of Mr. Tesla in this city at Columbia College followed up the Hertz experiments, but on a different line.

“Of course, the exact reason for the transmission of the electric current without any metallic conductor across a room from one plate to another is very obscure. It is very difficult, indeed, to explain it, and it can only be done by analogy, at least so that laymen can understand it. It is described as a sort of molecular bombardment, and that very term suggests the particular applicability of this phase of electricity when considered in reference to its possible or probable use in warfare. Now, as a matter of fact, while the experiment of Mr. Tesla was conducted by the use of plates at a short distance apart, say fifteen or twenty feet, there is really no inherent reason why this same result could not be produced at a distance of 5,000 feet. The only question is one of machinery. Can we make a machine having a sufficiently high voltage and sending an electric wave with sufficient rapidity? If we can, we can send a destructive current of electricity through the air for a distance of 5,000 feet or more. I might illustrate this so that it would appear more plain. Supposing, for instance, that two metal plates were made and one of them put up on the side of Fort Hamilton and the other on the side of Fort Wadsworth, and a dynamo attached to them of sufficient power, there is no reason why an incandescent lamp fastened to a passing vessel would not be illuminated when it came within range, so to speak, exactly as the lamp which was held in Mr. Tesla’s hand was.

“Now,” said Mr. Carty, “it is not a very great step from this phenomenon to expect that the electric impulse would not only light the lamp but would affect the ship itself.”

“How could that be done?”

“Well, it might derange the compass, it might do damage to machinery on board the ship, it might possibly heat the armor of a war ship so as seriously to disable it, and that is a most important suggestion in connection with this matter. I can see no inherent reason why this should not be so. The Tesla experiments have demonstrated a fact of electricity, and to my thinking it is only a question of our ability to construct a dynamo of sufficient power to generate the current.”

“What kind of a machine ought that to be?”

“Well, such a dynamo should be able to produce millions of electric waves every second, and should have a voltage approximating lightning itself.”

“Is such a machine possible?”

Mr. Carty hesitated a moment before replying to this question, and then said: “In the present stage of the science, of course, such a machine can only be dreamed of as a possibility, yet in electrical development dreams become realities with amazing rapidity. Why, we have in this city a very recent illustration of the truth of this. During the administration of Mayor Hewitt 1,200 volts were regarded as being uncontrollable in underground wires, and yet to-day from 20,000 to 30,000 are not uncommon in laboratory experiments, and in experimental installation. Now, it seems to me that there would be no greater progress displayed in the building of a dynamo capable of sending a current of electricity from the shore or from a float through the air to a war ship than the progress which has been gained in securing high voltage since the day when 1,200 volts was considered uncontrollable.”

“Would not such a machine be expensive?”

“Well, suppose it was. Undoubtedly it might be. But the matter of expense was not considered when the monitors were built. Suppose it cost as much to build a dynamo capable of doing these things as it would cost to build two or three battle ships, would the question of expense be considered? If such a machine can be built I would not want to say how far electricity could or could not be utilized by it for naval warfare. If such a machine be built its application would not be restricted to two plates facing each other. You couldn’t get a plate, of course, on an enemy’s warship. But that would not be necessary. The armor of the vessel itself would act as a plate, and all that it would be necessary for the attacking party to have would be the electric plate on shore or on a float, and so arranged that when the war ship came within range the circuit would be established and the attack complete.

“But even if it was found impossible to send a current through the air in this way, so as to disable the machinery of a war ship or to melt its plates, experiments which have recently been made indicate that it might be able thus to disable a crew. Mr. Tesla has made known the result of some experiments on the human body which show that when the body is subjected to the comparatively mild influence of a current passing through the air to two plates in a lecture room the body becomes perceptibly warm. Tesla, as a result of these experiments, suggests the possibility of a man visiting the North Pole in perfect comfort and standing there without any clothing on, being warmed by this current of electricity. Now, it does not require any great stretch of the imagination to suppose that this heating influence could be increased so as to produce the most disastrous effects upon the crew of a war ship.

“I sometimes give myself up to the imagination of what the Ericsson monitor of the future may be in the case of a great naval war. If the suggestions which have come to me from the Tesla experiment are developed into practical value as an energy of war, it is possible to conceive of a float constructed with a large plate and a dynamo carried out into the stream or bay or ocean, guided from shore and waiting for a war ship. When the war ship comes and presents its side, perhaps a mile or more away, a current is established between the armor and the plate on the float.”

“But supposing there is a fog or some non-conductor intervenes?”

“These waves will pass through fog or even through a brick wall, and this fact alone would revolutionize the ordinary means of defence. I can give you a simple illustration. These electric waves will go through solid matter without injury exactly as light goes through a window pane. You know that Prof. Bell set a current of electricity over a wave of light which carried a telephone message for a short distance, but the wave that he generated would be useless in case of a fog. In this case a fog or a stone wall would offer no resistance.

“Now, leaving the matter of war out of the consideration, it seems to me that these experiments may develop something of the highest value in the arts of peace. For instance, it would be perfectly feasible to generate a current of electricity which would penetrate a fog, and would be received by an apparatus on a steamship or vessel, and that devices might be invented by which the wave would be enabled to communicate intelligence. The enormous factors contained in these suggestions are less appalling than would have been the idea of the construction of the steamship City of Paris to ocean navigators and marine architects of the day of Columbus. There is, therefore, every reason to expect that in the future, and perhaps in the very near future, steamships will be provided with these apparatuses, and will be able to communicate with comparative ease at sea and through a fog. Some of the bottom principles in this suggestion have, in fact, already been made the subject of patents.

“Then, again, a besieged garrison might be able to communicate with its army, using the earth as a medium for the electric wave. There is no doubt whatever of the feasibility of this. I can demonstrate it any day. I can give an illustration of something that happened to me in Buffalo which proves it. I was talking over a long-distance telephone wire to friends in Cambridge, Mass., and I could hear with perfect distinctness the starting and the stopping of the electric railway cars running through the streets of Cambridge. Perhaps a more remarkable illustration occurred in Paris, when certain noises produced in the electric light station in London were heard at the telephone in Paris, having been carried over a circuit through the earth.

“I have not spoken with technical accuracy, because it is impossible, of course, for those who are not expert electricians to understand technical explanations, and I do not want to be considered as predicting positively that the things at which I have hinted will come to pass as far as the development of electricity as an engine of war is concerned. I might add that it has sometimes occurred to me that electricity might be used in another way.”

Mr. Carty took from his drawer a small glass tube closed at one end. In that end two fine wires had been inserted. Near the other end were two other wires. He smiled as he said:

“Possibly here is the germ of the great gun of the future. I have poured water into this vial and then stopped the open end with a cork driven in very firmly. Then, by passing a current of electricity through the water I have decomposed it so that it resolves itself into its gases; then, by sending a current of electricity through the upper wire the gases are exploded again into water and with such mighty force that it has blown the cork out and carried it many feet. Now, if a gun could be built strong enough to withstand the force of such an explosion it would be possible on a war ship to pump water from the sea into the gun, salt water being the best, then insert a cartridge or projectile, then decompose the water to gas, and then, by the electric spark, to explode this gas. It would have an impelling force of many atmospheres, and be far more powerful than powder. It has occurred to me that the tremendous explosive force which would endanger the gun might be overcome if we devised a process for slow-burning gas exactly as slow-burning powder is used. If such a gun is ever made, the chief advantage would be found in its safety, convenience, and possibly in a smaller cost. Whether the principle is ever applied to heavy guns or not, it may be developed satisfactorily for smaller arms, especially rapid-firing guns.”