JUNE 27, 1884.] 
no other known methods of making mild steels 
in large quantities. This is the only kind of 
steel in general use for boiler-plate, for bridge- 
work, or for general construction. The largest 
and finest steamships in the world are now 
made of this material, and their machinery is 
gradually absorbing a larger and larger pro- 
portion of the same kind of metal; and the 
time is probably not far distant when it will 
have completely displaced iron for all ordinary 
purposes of engineering construction, — as 
completely as has Bessemer steel displaced its 
- rival in the manufacture of rails. 
The great bridge over the Firth of Forth, 
with its two spans of seventeen hundred feet 
each, is to take forty-two thousand tons of 
Siemens steel. The one firm of Elder & Co. 
of Glasgow, the pioneers in the introduction 
of the marine compound engine and of steel 
ships, uses some twenty thousand tons of this 
steel per annum. In the ship-building trade, 
over two hundred and sixty thousand tons are 
now used each year. 
There are now over a hundred and fifty 
open-hearth furnaces in operation in Great 
Britain alone, exclusively for the manufacture 
of the Siemens steel. It has been found possi- 
ble to obtain temperatures sufficiently high to 
remove phosphorus, that bane of the steel- 
maker; and now moderately phosphuretted 
ores are worked for steel. The scrap-iron used 
is to a considerable extent obtained from the 
Bessemer works, which supply rail-ends and 
other waste. 
Space does not permit more than a mention 
of the other minor, but nevertheless great, 
‘creators of the age of steel.’ Sir Joseph 
Whitworth has, by a system of compression of 
the molten and solidifying ingot, given us a 
steel so perfectly sound and free from ‘ blow- 
holes’ that it may be used for a thousand 
purposes for which ordinary steel is entirely 
unfitted. This steel is made by the ordinary 
processes, and, when poured into the ingot, is 
immediately placed under the plunger of a very 
powerful hydraulic press, and there subjected 
to a pressure of a thousand or two thousand 
tons ; under which enormous load every pore is 
closed up, and the steel solidifies in a compact 
mass of such fineness of structure, that no 
microscope, and no physical or mechanical test, 
ean detect the slightest defect in homogeneous- 
ness. Its strength and its ductility are such 
that the inventor tests the ordnance which he 
makes of this metal by securing the shot in the 
gun so that it cannot be driven out; and then, 
firing the charge behind it, the whole mass of 
gas resulting from the combustion blows out at 
SCIENCE. 793 
the ‘ vent’ without injury to the gun. Nosuch 
test was ever dreamed of by any ordnance 
officer, or attempted with any other kind of 
ordnance metal. 
Sir John Brown, the proprietor of the great 
iron and steel works at Sheffield, famous for 
the magnitude of the armor-plates often made 
there, was the first manufacturer in Great 
Britain to countenance Bessemer in his en- 
deavor to make a new steel, and was the first 
to put up a Bessemer converter, after the early 
experiments of the inventor had indicated a 
probable success. ‘The armor-plating of ships 
— an invention of our countryman, Robert L. 
Stevens of Hoboken — was adopted in England 
during the Crimean war, at about the time that 
the Emperor Napoleon made the first attempt 
to make armored vessels of service in attack- 
ing the forts at Sevastopol. Sir John Brown 
was one of the first of the British iron manu- 
facturers to fit up works for the purpose of 
making heavy plate. He soon added Besse- 
mer works to his establishment, and produced 
steel for the general market. His armor-plate 
is now made as a ‘compound’ plate, consist- 
ing of an iron backing, with a facing of steel,— 
a combination of which more is expected than 
from the simple construction. The magnitude 
of the works may be imagined from the fact 
that there are in use a hundred and sixty 
steam-boilers, supplying steam to the amount 
of eleven thousand or twelve thousand horse- 
power. 
Other great promoters of the revolution now 
in progress are Messrs. Gilchrist and Thomas 
and Snelus: they have done much toward the 
reduction of the cost of making steel by the 
modern processes, by making it possible to use 
the cheap phosphuretted ores which had pre- 
viously been unavailable. The new method of 
operation of the Bessemer process, which has 
effected this change, and which, as Mr. Carnegie 
says, has ‘“‘ done more for England’s greatness 
than all her kings and queens and aristocracy 
together,’’ consists simply in the lining of the 
converter with materials having a basic reac- 
tion, and in the introduction of similar material 
with the charge. Lime is the base found best 
adapted to the purpose; and its use has, after 
long experiment and the expenditure of much 
time and money, been made practicable by 
Messrs. Thomas and Gilchrist, and Mr. Snelus. 
At extremely high temperatures, and in the 
presence of lime, phosphorus will pass from 
the molten iron in the converter into the lime 
with which it meets in the lining of the vessel, 
and which is added before the blow; and the 
steel is thus freed from its most persistent and 
