7 Sir Henry Bessemer 7

and vast profits flowed in. It became clear that “mild

steel”—as it was known to distinguish it from the hard

tool steels—could more clearly and reliably be used in

place of wrought iron for ship plate, girders, sheet, rods,

wire, rivets, and other items. The invention of the open-

hearth (Siemens-Martin) process in the late 1860s

eventually outstripped that of the Bessemer process. This

has now yielded place, in great measure, to oxygen steel-

making, which is a further development and refinement of

the Bessemer process.

In his later years—the process had not become a clear

success until he was nearing 70—Bessemer continued to

invent and make discoveries. The solar furnace he built

was more than a successful toy; he designed and built an

astronomical telescope for his own amusement; and he

developed a set of machines for polishing diamonds that

helped to reestablish that trade in London.

Apart from his knighthood, he received many honours,

such as the Fellowship of the Royal Society. Bessemer’s

An Autobiography (1905), with a concluding chapter by

his son, Henry Bessemer, is the only comprehensive

biography and the source of most material written about

him since.

Samuel Colt

(b. July 19, 1814, Hartford, Conn., U.S.—d. Jan. 10, 1862, Hartford)

S

amuel Colt was an American firearms manufacturer

who popularized the revolver.

Until the mid-1840s most pistols were single-shot

muzzle-loaders fired by wheel lock, flintlock, and percussion

ignition systems. Some early pistols, known as “pepper-

boxes,” had several barrels, and as early as the 17th century

pistols were manufactured with a revolving chamber to

load cartridges successively into a single barrel. However,