Later in the war, when he was in France, he discussed the question with the French gas people and reminded them that he had made this suggestion in 1914. They agreed with him that had they tried this on a twenty-five-kilometer front they probably would have broken through.
Shortly after America’s entry into the war, a meeting of the Naval Consulting Board was held in New York at the request of Admiral Sims. It consisted of a group of civilian scientists, engineers, and also naval officers, who were expected to think up useful ideas for the Navy. Sims was about to sail for England to discuss antisubmarine activities with the British Admiralty and wanted to arm himself with the latest suggestions. Dr. Wood, though not a member of the board, had been invited to participate.
During the exchange of ideas, Dr. Wood suggested that experiments be made with what are now called “blisters”. His idea was to have an outer shell of thin steel subdivided into a number of air-filled chambers, welded to the hull on the outside of warships, below the water line. A torpedo would explode on contact with the outer shell and the gases would expand into the air space and lose most of their destructive force. He said the idea could be tried at small cost on some condemned hull, substituting a bomb for the torpedo. Hudson Maxim, the explosive expert of the board, leaped to his feet and shouted, “Professor Wood is all wrong. The compartments should be filled with water instead of air”. This was perfect nonsense, and there were cries of “No, no”.
Sims rapped on the desk and said that further discussion would be a waste of time, as the British Admiralty had informed him no antitorpedo defense that involved the building of any structure whatsoever on the outside of the hull would be considered.
The English battleships and cruisers were equipped with “blisters” in the latter part of the war, and they are shown in many photographs of ships engaged in the present war. The principle of antitorpedo air pockets is now standard practice in naval construction, but they are incorporated within the hull. It seems strange that Sims knew nothing about them at the time of the meeting in New York, if they were already in use in the British Navy.
It was at this same meeting that Wood amazed them all — and shocked most of them purple — by suggesting that it might be a bright idea to train seals to chase submarines! They laughed, and some member tried to start a new topic. But Wood stood up and claimed the floor. He was a great scientist, and so they listened to him — and so help me God, the British Admiralty later tried it!
Wood began by pointing out that seals could be taught almost anything that dogs could. A collar with a steel wire attached to a large hollow ball of rubber painted scarlet and dragged along on the surface would enable the sub-chaser to follow the seal! A. G. Webster, professor of physics at Clark University, protested against wasting the board’s time with such a silly suggestion, and another member said you couldn’t train an animal to do anything it had no natural instinct for. Wood countered by asking, “How about fox hounds following a bag of anise seed?” and suggested that it would do no harm to consult a professional seal-trainer, who would be the one best qualified to decide whether the suggestion was worth trying.
Sims took the idea over to London, and within a month the Admiralty was conducting experiments with seals, on a lake in Wales, admitting subsequently that the idea had come through the United States naval attaché in London. They found that seals could be trained to hunt out and follow the sound of a submarine’s propeller, and perhaps the odors from the oil and exhausts. The experiments were commenced with an electrical “buzzer”, and the hungry seal was rewarded with a fresh fish as soon as he located or followed it. In experiments with their own submarines, they had what Dr. Wood characterized as “considerable success”.
The “water bloodhounds” never trailed or caught any German U-boats, however, and as a would-be honest biographer I am compelled to say that the “considerable success” attributed by Dr. Wood to his trained seals was not a determinate factor in marine warfare. The seals had been muzzled to discourage independent fishing expeditions of their own, but one of the difficulties encountered was that they had a tendency to run off after schools of herring anyway — just as the bloodhound abandons Eliza or a convict to go off chasing rabbits. Other difficulties were that the seals not infrequently followed wrong ships, and that the floats attached to their collars could not be made large enough to be clearly visible at great distances or in fogs. The seals did learn to trail oil, and learned for that matter to trail the sound of screw propellers, and therefore proved Dr. Wood’s contention — but the whole business leaves me with the conviction that the idea was even more “screwy” than the sterns of the U-boats. One thing of importance did result from these fantastic experiments. They proved that the seals could hear perfectly well when swimming at full speed under water, and this discovery was responsible for an improvement in the performance of the hydrophones or “listening trumpets” which were towed under water and picked up propeller sounds. The noises made by the rush of water across the trumpet’s mouth drowned out fainter sounds, and it had been necessary to slow down or stop the chaser for listening purposes. By studying the contours of the seal’s ears and applying their design to the ears of the hydrophones, their performance was greatly improved.
It was after Wood had his major’s commission and was working with the Bureau of Inventions in Paris, in co-operation with all the Allies, that he conceived what has since been variously called the “spider shell”, the “spaghetti shell”, the “piano-wire shell”, and the “parachute shell”. It perhaps happily combines, as I see it, the two paradoxical categories of his war inventions. It is certainly fantastic, yet it must be pragmatically sound, since the British were reported to be reviving and using it in the air defense of London in 1940 — and international press services were attributing its origin to “Professor R. W. Wood, Johns Hopkins University physicist”.
Here’s what Wood says about it.
In discussing defense against hostile aircraft with a number of officers of the French air force at one of the aerodromes, in November, 1917, I suggested that experiments be made with shells containing a coil of steel piano wire — the shells to be constructed like the “parachute bomb” in pyrotechnics. One end of the coil was to be attached to the base of the shell and the other to a small silk parachute packed in the nose. On explosion the base would be driven downward, unwinding the coil of wire, while the parachute would open and drift along with the long strand of wire dangling below, like the spider that spins a long thread into the breeze, and then floats away carried by his thread. I also suggested this at one of the meetings of the Bureau of Inventions in Paris, calling it the “spider shell”, but nothing appears to have been done with the idea at the time. After the war I alluded to it in a number of public lectures on the relation of scientific research to warfare. Several paper patents appear to have been taken out by various parties in the interval between the two world wars. According to press accounts the wire strands used in the present war were not provided with parachutes and would fall rapidly.
During all this hectic time, while Wood was inventing war gadgets and later, when we went in, pulling every possible human wire to get into uniform and actual service “over there”, he wasn’t neglecting his purely scientific work.
In the early part of the summer of 1916, he was busy in East Hampton developing a new filter for the photography of the planets by ultraviolet light, which he planned to use with the great sixty-inch reflecting telescope of the Mount Wilson Observatory in California. The filter consisted of a cell made by covering the ends of a short section cut from a square glass bottle with plates of “uriol” glass. This cell was filled with bromine vapor, which he had found to be transparent to ultraviolet light but opaque to all other rays capable of acting on the photographic plate.