It was many years after this, however, before the metal was obtained in a state of purity and its properties satisfactorily determined, and it was much later still when nickel, in a state of comparative purity, became an article of commerce; indeed, until recently it was hardly known in the pure state outside of the laboratory. In 1804 Richter experimented with this metal and obtained it fairly pure by reducing the oxide with carbon in an earthen crucible. Almost seventy years later, Wharton, of the Camden Nickel Works, Camden, N. J., who has devoted so much attention to the metallurgy of nickel, exhibited at the Vienna Exposition vessels of pure forged nickel, which he made by strongly compressing the spongy mass obtained by reduction of the oxide. These exhibits at Vienna, and similar ones at Philadelphia in 1876, and at Paris in 1878, received but scant attention from scientific visitors. Chemists and metallurgists, as a rule, supposed they were nickel alloy, and were somewhat incredulous when informed that the objects were pure nickel; in fact, the commercial production of pure nickel by Wharton, as evidenced by these exhibits, was a genuine surprise to the metallurgical world.
A further advance in the metallurgy of nickel was made by Fleitmann, of Iserlohn, Westphalia, in 1879. He found that the purest nickel he could obtain on a commercial scale had a brittleness which did not belong to the pure metal, and in the course of investigation he was led to believe that the brittleness was caused by occluded carbonic oxide. He decided to attempt the removal of this by adding magnesium in minute quantity to the molten nickel, and was successful beyond expectation, for the nickel thus treated quickly loses its brittleness.
As to the properties of nickel, it will suffice to say that it is a hard silver-white metal with a steel-gray tinge; it may be rolled into thin plate or drawn into wire; it is not readily oxidized; it is attracted by the magnet and readily assumes a polar condition.
Turning now to consider the uses of this metal, we find that Thénard in 1825, in his Traité de Chimie, stated that nickel was not employed for any practical purpose. This statement is true only in reference to the pure metal; for, just as brass was known and used long before zinc was isolated, so nickel alloys were known and used long before Cronstedt's discovery of the metal. The Chinese appear to have been among the earliest users of nickel alloys, for as early as 1776 it was pointed out that Chinese packfong—i. e., white copper—is an alloy of copper, zinc, and nickel. The beginning of the manufacture of these alloys in Europe is due to a somewhat curious circumstance. In the old slags from disused copper-smelting works at Suhl in Prussian Saxony, and once known as the armory of Germany, white granules of metal were found.