Inventions in the Century

by William Henry Doolittle

The progress of screw-making had been such that in 1840, by the machines then in use for cutting, slotting, shaving, threading, and heading, twenty men and boys were enabled to manufacture 20,000 screws in a day. Thirty-five years later two girls tending two machines were enabled to manufacture 240,000 screws a day. Since then the process has proceeded at even a greater rate. So great is the consumption of screws that it would be utterly impossible to supply the demand by the processes in vogue sixty years ago.

In England’s first great International Fair, in 1851, a new world of metallurgical products, implements, processes, and metal-working tools, were among the grand results of the half century’s inventions which were exhibited to the assembled nations. The leading exhibitor in the line of self-acting lathes, planing, slotting, drilling and boring machines was J. Whitworth & Co., of Manchester, England. Here were for the first time revealed in a compact form those machines which shaped metal as wood alone had been previously shaped. But another quarter of a century brought still grander results, which were displayed at the Centennial Exhibition at Philadelphia, in 1876.

As J. Whitworth & Co. were the leading exhibitors at London in 1851, so were William Sellers & Co., of Philadelphia, the leading exhibitors in the 1876 exhibition. As showing the progress of the century, the official report, made in this class by citizens of other countries than America, set forth that this exhibit of the latter company, “in extent and value, in extraordinary variety and originality, was probably without parallel in the past history of international exhibitions.” Language seemed to be inadequate to enable the committee to describe satisfactorily the extreme refinement in every detail, the superior quality of material and workmanship, the mathematical accuracy, the beautiful outlines, the perfection in strength and form, and the scientific skill displayed in the remarkable assemblage of this class of machinery at that exhibition.

An exhibit on that occasion made by Messrs. Hoopes & Townsend of Philadelphia attracted great attention by the fact that the doctrine of the flow of solid metal, so well expounded by that eminent French scientist, M. Tresca, was therein well illustrated. It consisted of a large collection of bolts and screws which had been cold-punched, as well as of elevator and carrier chains, the links of which had been so punched. This punching of the cold metal without cutting, boring, drilling, hammering, or otherwise shaping the metal, was indeed a revelation.

So also at this Exhibition was a finer collection of machine-made horseshoes than had ever previously been presented to the world. A better and more intelligent and refined treatment of that noble animal, the horse, and especially in the care of his feet, had sprung up during the last half century, conspicuously advocated by Mr. Fleming in England, and followed promptly in America and elsewhere. Within the last forty years nearly two hundred patents have been taken out in the United States alone for machines for making horseshoes. Prejudices, jealousies and objections of all kinds were raised at first against the machine-made horseshoe, as well as the horseshoe nail, but the horses have won, and the blacksmiths have been benefited despite their early objections. The smiths make larger incomes in buying and applying the machine-made shoes. The shoes are not only hammered into shape on the machine, but there are machines for stamping them out from metal at a single blow; for compressing several thicknesses of raw hide and moulding them in a steel mould, producing a light, elastic shoe, and without calks; furnishing shoes for defective hoofs, flexible shoes for the relief and cure of contracted or flat feet, shoes formed with a joint at the toe, and light, hard shoes made of aluminium.

Tube Making.—Instead of heating strips of metal and welding the edges together, tubes may now be made seamless by rolling the heated metal around a solid heated rod; or by placing a hot ingot in a die and forcing a mandrel through the ingot. And as to tube and metal bending, there are wonderful machines which bend sheets of metal into great tubes, funnels, ship masts and cylinders.

Welding.—As to welding—the seams, instead of being hammered, are now formed by melting and condensing the edges, or adjoining parts, by the electric current.

Annealing and Tempering.—Steel wire and plates are now tempered and annealed by electricity. It is found that they can be heated to a high temperature more quickly and evenly by the electric current passed through them than by combustion, and the process is much used in making clock and watch springs.

One way of hardening plates, especially armour plates, by what is called the Harveyized process, is by embedding the face of the plate in carbon, protecting the back and sides with sand, heating to about the melting point of cast iron, and then hardening the face by chilling, or otherwise.

Coating with Metal.—Although covering metal with metal has been practised from the earliest times, accomplished by heating and hammering, it was not until this century that electro-plating, and plating by chemical processes, as by dipping the metal into certain chemical solutions, and by the use of automatic machinery, were adopted. It was in the early part of the century that Volta discovered that in the voltaic battery certain metallic salts were reduced to their elements and deposited at the negative pole; and that Wollaston demonstrated how a silver plate in bath of sulphate of copper through which a current was passed became covered with copper. Then in 1838, Spencer applied these principles in making casts, and Jacobi in Russia shortly after electro-gilded a dome of a cathedral in St. Petersburg. Space will not permit the enumeration of the vast variety of processes and machines for coating and gilding that have since followed.