64 
THE PRINCIPAL FLOOR. 
given out by any friction of the blade, either by bending or 
otherwise. 
Toledo under the Romans, and in the time of the Moors, was 
celebrated for the admirable temper of its swords, “ which is 
chiefly attributable,” says a writer on the Toledo blades, “ to 
some favourable quality in the water of the Tagus, used in 
“ tempering the steel.” 
Andrew of Ferrara has associated his name with the swords 
of his manufacture, “Andrea Ferrara” This sword maker was 
considered, in his time, to be the only man in Great Britain who 
knew how to temper a sword in such a way that the point 
should bend to touch the hilt and spring back again uninjured. 
He is said to have resided in the Highlands of Scotland, where 
he employed many men in forging his swords, devoting his 
entire attention to tempering them. This operation he performed 
in a dark cellar, the better to enable him to distinguish the 
colours produced by heat on the blade, upon which everything 
depended. 
Swords appear to have been made at Birmingham from a 
very early period, and sword-making is now one of its staple 
trades. The forges of Sheffield, however, furnish a large quan- 
tity of bars of steel, called sword moulds. One of these is 
shown, as also the fastening of the tang , which is of iron ; and 
the results after the different stages of forging. It is hardened 
by heating it until it becomes worm red, and then dipping it, 
point downwards, in a tub of cold water. It is tempered by 
drawing it through the fire several times, until it exhibits a 
bluish oxidation on the surface. It is subsequently polished 
and mounted. 
Manufacture of Gun- barrels. — The principal object sought in 
the manufacture of a gun-barrel is its strength. It should 
possess so much tenacity as will ensure its resisting the sudden 
shock to which it is exposed in projecting the ball by the 
explosive force of gunpowder. The series here exhibited 
illustrates only the old method, now largely superseded. Scrap 
iron is employed for inferior barrels, horse-shoe nails and 
scrap steel are (or were) taken for superior kinds; these are 
welded into flat bars ; the bars of iron and steel are again 
welded together, and formed into square bars. If a number 
of straight bars were welded together to form a barrel, they 
would be liable to open along the lines of welding ; at all 
events, such a gun-barrel would not be nearly so safe as one 
made of the same bars formed into a helix and then welded 
into a tube. 
By altering the arrangement of the fibres of the iron there is 
produced a lifferent pattern on the surface of the barrel, when 
they are rendered visible by polishing. Thus, one bar is twisted 
to the right, another is twisted to the left hand. Now these 
when twisted on a mandril are welded into a barrel, which w-ill 
exhibit an involved pattern. If they are combined, or if an 
untwisted bar is placed between them, and they are then 
