Accidental Observation.
Accident has played a noteworthy part in both discovery and invention. Nathaniel Hayward long ago remarked that sulphur deprives rubber of stickiness. Charles Goodyear one day combined some rubber and sulphur by way of experiment; quite by accident he overturned part of the mixture upon a hot stove. He saw in a moment that heat is essential to make rubber insensible to both heat and cold: he had indeed discovered vulcanization. Examples of this kind abound in the history of every art. As far afield as the war on insect pests in France a priceless discovery was hit upon unsought a few years ago. One autumn the vines were still suffering from phylloxera when a mildew caused by a fungus began to do serious damage to crops. Through the spraying of vines with blue-stone to prevent pilfering of fruit, it was noticed that the fungus was killed, leading to the most telling mode of attack on many of the pests which assail leaves, flowers and fruit.
James Hargreaves once saw a spinning-wheel overturned, when both the wheel and spindle continued to revolve on the floor. As he observed the spindle thus changed from a horizontal to an upright position it occurred to him that if a number of spindles were thus placed, side by side, several threads might be spun at once instead of a single thread. This was the origin of the spinning jenny; an invention which has parallels in the multiple drills, the gang-saws, and other machinery which take a task once executed by a single drill, saw or punch, and simultaneously perform it with ten, twenty, or a hundred drills, saws, or punches.
About thirty years before Josiah Wedgwood laid the foundation of his future eminence, a chance observation gave rise to improvement in the earthenwares of Staffordshire. A potter from Burslem, the centre of the potteries and the birthplace of Wedgwood, in traveling to London on horseback was detained on the road by the inflamed eyes of his horse. Seeing the hostler, the horse-doctor of those times, burn a piece of flint, and, having reduced it to a fine powder, apply it as a specific to the diseased eyes, it occurred to the potter that this beautiful white powder, if combined with the clay used in his craft, might improve the strength and color of his ware. An experiment succeeded, and so began English white ware, since manufactured on an immense scale.
More important than this discovery of a new use for flint powder was the discovery, also accidental, of electro-magnetism by Professor Oersted of Copenhagen. The incident is thus related in a letter to Michael Faraday from Professor Christian Hansteen:—
“Professor Oersted was a man of genius, but he was a very unhappy experimenter; he could not manipulate instruments. He must always have an assistant, or one of his auditors who had easy hands, to arrange the experiment; I have often in this way assisted him. In the eighteenth century there was a general thought that there was a great conformity, and perhaps identity, between the electrical and magnetical forces; and it was a question how to demonstrate it by experiments. Oersted tried to place the wire of his galvanic battery perpendicular (at right angles) over the magnetic needle, but remarked no sensible motion. Once, after the end of his lecture, as he had used a strong galvanic battery to other experiments, he said, ‘Let us now once, as the battery is in activity, try to place the wire parallel with the needle;’ as this was done he was quite struck with perplexity by seeing the needle making a great oscillation (almost at right angles with the magnetic meridian). Then he said, ‘Let us now invert the direction of the current;’ and the needle deviated in the contrary direction. Thus the great detection was made; and it has been said, not without reason, that ‘he tumbled over it by accident.’ He had not before any more idea than any other person that the force should be transversal.”
Granting that many important discoveries thus come about in ways beyond human foresight, accident alone will not produce an invention. As Dr. Ernst Mach reminds us, in every such case the inquirer is obliged to take note of the new fact, to recognize its significance, to detect the part it plays, or can be made to play, in a new structure, or in a novel and sound generalization. What he sees before him, others also have seen, perhaps many times; he is the first to notice it as it deserves to be noticed, simply because he has an eye earnestly desiring to behold just such a fact as this and use it to bridge a gap either in art or explanation.
Let us take a case where an accident, well observed, has meant a golden discovery. One day during a trip on the Thames in a steamer propelled by an Archimedean screw devised by Francis Pettit Smith, the propeller struck an obstacle in the water, so that about one half of the length of the screw was broken off; it was noticed that the vessel immediately shot ahead at a much quickened pace. In consequence of this discovery, a new short screw was fitted to the vessel and with this new propeller the steamer went uniformly faster than before.
Perforated Sails for Ships.
In craft built ages before steamers were designed, fishermen have observed that sails torn in the middle, if the rents were not too big, were more effective than when new and whole. What thus began in sheer wear, or accidental damage, is now imitated of set purpose. Under the equator one may often see small craft whose sails are matting woven with large openings, as the sailors say “to let out the wind.” The mariners of Carthegena, St. Thomas, and other islands of the West Indies, know that a ship goes better thus than if her sails were each one continuous breadth of canvas. Japanese junks of clipper builds have sails made of vertical breadths laced together so as to leave large apertures free to the air. Why is this breeziness of structure profitable? Because against the concave surface of an ordinary sail the wind rebounds so as to hinder its impulsive effect; through an aperture the air rushes in a continuous current and no rebound takes place. For a like reason, and with similar gain, Chinese rudders are made with separated boards or planks. The stream of water passing through such a rudder would exert an undesirable back pressure in a rudder of solid form.