DISCOVERY 



213 



in a paper-mill omit to add any size to the pulp, and the 

 result is a parcel of paper that is thrown aside as waste- 

 Someone, happening to use a scrap of this " waste " 

 to write a note, discovers its absorbent character, and 

 straightwaj^ blotting-paper is invented. The feeder 

 of a lithographic machine fails to place a sheet of paper 

 in position at the right moment, and consequently it 

 does not pass through the machine. But the work on 

 the printing surface leaves its full impression upon the 

 covering of the printing cylinder, and when the next 

 sheet passes through it receives the direct impression 

 from the printing surface whilst an indirect or set-off 

 print is made from the back upon the paper. Mr. Ira 

 \V. Rubel happens to be standing by, and the accident 

 starts him on experiments which lead to the invention 

 of the off-set method of printing. 



The burning of a starch factory on the banks of the 

 Liffey reveals the adhesive qualities of scorched starch 

 mi.xed with water, and introduces to the world a new 

 and cheap gum. A glass-cutter at Nuremberg accident- 

 ally lets some aquafortis drop on his spectacles, and 

 etching on glass soon follows. While researches are 

 being carried out in a German laboratory, a ther- 

 mometer breaks, and the mercury runs out into a heated 

 mixture of naphthalene. The oxidation completed by 

 the catalytic action of the sulphate of mercury resulting, 

 shows a method of overcoming the one hindrance in the 

 way of making the manufacture of synthetic indigo a 

 commercial success. A laboratory attendant supplies 

 antifebrin in place of naphthalene, and his blunder 

 leads to the discovery of the anti-pyretic properties of 

 the former substance. 



The history of photography is full of examples of the 

 fruitfulness of chance oversights. Daguerre is careless 

 enough to lay down a silver spoon upon a plate that he 

 has treated with iodine. He notices that the image of 

 the spoon is retained, and thus learns that a plate so 

 treated is sensitive to light. Through putting aside 

 one of his silver plates in a cupboard overnight, he dis- 

 covers the effect of vapour of mercury on a sensitive 

 plate. Mr. Fox Talbot accidentally lets one of his 

 exposed papers come in contact with a solution of nut- 

 galls, and thus ascertains the virtue of gallic acid. That 

 uranium gives off in\asible rays is discovered by 

 Becquerel through putting some of it by in a drawer 

 with a photographic plate, and finding an image formed 

 upon the plate though it has not been exposed to sun- 

 hght. 



This brief selection of items from the history of 

 photography is a reminder that not all mentally stimu- 

 lating accidents are associated with breakages or 

 blunders. The part that accident plays in the process is 

 the casual bringing together of circumstances in which 

 the alert and observant mind discerns possibilities 

 hitherto unrecognised. The point is that the oppor- 



tunity of observation comes by accident and is not de- 

 liberately sought or arranged. It was not from any set 

 purjxjse of forwarding his own scientific experiments 

 that Montgolficr one day undertook the responsibility 

 of airing his wife's gowns, when she was called to leave 

 the house. He observed, while engaged on this task, 

 that the gowns became inflated and tended to rise when 

 filled with heated air ; and Madame Montgolfier, on her 

 return, found her husband sending up little paper 

 balloons and thus originating the invention which made 

 him famous. 



In such instances the obvious essential, if there is 

 to be any result of value, is that the observer shall have 

 that capacity of detecting analogies which Professor 

 Bain described as " the intellectual power of Similarity." 

 He discerns the underlying identity of processes that, 

 on the face of them, seem to have no connection what- 

 ever. Some years ago an Ohio business man had a shop 

 in a good situation, and many customers, but somehow 

 it was not profitable. There was evidently something 

 lacking in his methods, and he worried so much on the 

 subject that he found it desirable to take a holiday. 

 While on his way to Europe he was standing one day 

 in the ship's engine-room, when his attention was 

 attracted by the automatic indicator of the propeller 

 shaft's revolutions. The question suddenly occurred 

 to him : " \\Tiy not devise a machine for recording 

 sales in a shop ? " Hence the invention of the cash 

 register. At the hearing of a Dunlop appeal case in 

 the House of Lords in December, 1920, it was mentioned 

 that the idea of the pneumatic tyre was suggested by 

 the tying of a piece of water-piping around the wheel 

 of a wheelbarrow. The use of the stiff collar is due to 

 the mental alertness of a blacksmith's wife in Troy, 

 N.Y., who, somewhere about the year 1825, was w^ashing 

 her husband's shirts, which, according to the unvarying 

 custom of those days, had the collars attached to them. 

 It occurred to her that a shirt lasted clean longer than 

 the collar. She started making collars separate from 

 shirts and seUing them to her neighbours. The idea 

 caught on, and before 1S40 several collar-making com- 

 panies were doing a good business. When one is talk- 

 ing about collars one recalls another device which is 

 due to the forethought of a British officer's wife for the 

 safety of her husband. As Sir George Lusk was about 

 to start on one of his Indian campaigns. Lady Lusk 

 sewed some strips of chain under the cloth between the 

 collar and the shoulder of his tunic as a protection 

 against chance sabre cuts. This answered so well that 

 chain shoulder straps were afterwards officially adopted 

 for all ranks in the British Army. It was quite another 

 type of accident that put George Westinghouse on the 

 track of his chief invention. While on a railway 

 journey in America he was aroused to compassion by 

 the quiet persistence of a tired-looking young woman 



