The Part of Chance in Progress.

Fortunate Accidents Frequently Have Opened the Way to the Discovery of Important Truths Before the Searchlights of Science and Invention Were Brought Into Play.

Nature has her own ways of telling her secrets to man, and the commonest of those ways is what man chooses to call chance or accident. The words are convenient names and that is about all we know of the phenomena which they are used to describe.

Below are given the stories of a number of important discoveries made by accident. Perhaps it will occur to the reader that none of the discoveries was really accidental, since in each case it was the witnessing of the accident by an intelligent human being which aroused in the mind of that human being the train of thought leading to the discovery. An Australian black might watch a swaying chandelier for ten years, and he would never discover the pendulum. As a rule, special knowledge is required to make "discoveries by accident."

But the apparent working of chance in the incidents told here is obvious:

The power of lenses, as applied to the telescope, was discovered by a watchmaker's apprentice. While holding spectacle-glasses between his thumb and finger, he was startled at the suddenly enlarged appearance of a neighboring church spire.

The art of etching upon glass was discovered by a Nuremberg glass-cutter. By accident a few drops of aqua fortis fell upon his spectacles. He noticed that the glass became corroded and softened where the acid had touched it. That was hint enough. He drew figures upon glass, with varnish, applied the corroding fluid, then cut away the glass around the drawing. When the varnish was removed, the figures appeared raised upon a dark ground.

The swaying to and fro of a chandelier in the cathedral at Pisa suggested to Galileo the application of the pendulum.

The art of lithography was perfected through suggestions made by accident. A poor musician was curious to know whether music could not be etched upon stone as well as copper.

After he had prepared his slab, his mother asked him to make a memorandum of such clothes as she proposed to send away to be washed. Not having pen, ink, and paper convenient, he wrote the list on the stone with the etching preparation, intending to make a copy of it at leisure.

A few days later, when about to clean the stone, he wondered what effect nitric acid would have upon it. He applied the acid, and in a few minutes saw the writing standing out in relief. The next step necessary was simply to ink the stone and take off an impression.

The composition of which printing-rollers are made was discovered by a country printer in England. It was the established custom to ink the type on a printing-press with a pelt-ball—an ink-soaked roll of sheepskin. Having mislaid his pelt-ball, the ingenious Englishman inked the type with a piece of soft glue which had fallen out of the glue-pot. It was such an excellent substitute that, after mixing molasses with the glue to give the mass proper consistency, the old pelt-ball was entirely discarded.

The shop of a London tobacconist, by the name of Lundyfoot, was destroyed by fire. While he was gazing dolefully into the smoldering ruins, he noticed that his poorer neighbors were gathering the snuff from the canisters. He tested the snuff for himself, and discovered that the fire had largely improved its pungency and aroma.

It was a hint worth profiting by. He secured another shop, built a lot of ovens, subjecting the snuff to a heating process, gave the brand a peculiar name, and in a few years became rich.

The Origin of Tinted Paper.

The origin of blue tinted paper came about by a mere slip of the hand.

The wife of William East, an English paper-maker, accidentally let a blue-bag fall into one of the vats of pulp. The workmen were astonished when they saw the peculiar color of the paper, while Mr. East was highly incensed over what he considered a grave pecuniary loss. His wife was so much frightened that she did not confess her agency in the matter.

After storing the damaged paper for four years, Mr. East sent it to his agent in London, with the instruction to sell it for what it would bring. The paper was accepted as an attractive novelty, and was disposed of at quite an advance over the market price.

Mr. East was astonished at receiving an order for another large invoice of the paper. He was without the secret, and found himself in a dilemma. Upon mentioning it to his wife, she told him about the accident. He kept the secret, and the demand for the novel tint far exceeded his ability to supply the article.

A Brighton stationer took a fancy for dressing his show window with piles of writing-paper, rising gradually from the largest to the smallest size in use; and to finish his pyramids off nicely he cut cards to bring them to a point.

Taking these cards for diminutive note-paper, lady customers were continually wanting some of "that lovely little paper," and the stationer found it advantageous to cut paper to the desired pattern.

As there was no space for addressing the notelets after they were folded, he, after much thought, invented the envelope, which he cut by the aid of metal plates made for the purpose.

The sale increased so rapidly that he was unable to produce the envelopes fast enough, so he commissioned a dozen houses to make them for him, and thus set going an important branch of the manufacturing stationery trade.

Asphalt as a Street Pavement.

All forms of bituminous pavements, whether manufactured from natural or artificial asphalt, are, in fact, artificial stone pavements. The industry started with the use of the natural rock asphalt from the mines in the Val de Travers, Canton Neuchatel, Switzerland.

The mines were discovered in 1721, but it was in 1849 that the utility of their product as a road covering was first noticed. The rock was then being mined for the purpose of extracting the bitumen contained in it for its use in medicine and the arts. It is a limestone, impregnated with bitumen, of which it yields, on analysis, from eight to fourteen per cent.

It was observed that pieces of rock which fell from a wagon were crushed by the wheels, and under the combined influence of the traffic and heat of the sun, a good road surface was produced.

A macadam road of asphalt rock was then made, which gave very good results, and finally, in 1854, a portion of the Rue Bergère was laid in Paris of compressed asphalt on a concrete foundation. From Paris it extended to London, being laid on Threadneedle Street in 1869, and Cheapside in 1870.