308 
MINUTES OF PEOCEEDINGS OF 
guard, and lever. Most of these parts are of wrought-iron, being 
blocked out from a bar; that is, the end of the bar is brought to a 
white heat, and placed under a Nasmyth's hammer, the anvil and 
hammer of which are reciprocally recessed to the shape of the article 
required. 
The article, thus roughly forged, is brought by a series of machine 
operations to exact size, shape, and finish; for example, the trigger 
guard undergoes clipping, slotting, milling, drilling, &c., &c.—in all, 
over 70 operations—before it passes into the final viewer's or gauger's 
hands. 
The trigger guard furnishes us also with an illustration of “ blueing" 
•—an operation which it and the " body " (steel), as well as the bands and 
nose-cap of the stock, finally undergo, for the purpose of making them 
not liable to rust. It consists, simply, in coating the surface with a thin 
film of oxide, which is effected by heating the article in a sand bath until 
it assumes a dark-blue colour. The parts which are exposed to hard 
usage or friction—namely, the lever and block (as also the heel-plate of 
the stock)—are “ case-hardened"; i.e. } hardened on the outside by 
means of heating with some substance containing carbon. At Enfield 
the article is put in a cast-iron pan filled with bone-dust, heated to 
redness, and allowed to cool, by which time it has assumed a mottled 
appearance. 
The Main Spring is made first by winding the soft steel wire round a 
Cylinder furnished with a raised helix, then heating the spiral thus formed 
to redness and suddenly cooling it, and then tempering it in the usual 
way— i.e.j raising it to a certain heat (in this case until it would cause oil 
to flash) and allowing it to cool naturally. This spiral spring is sub¬ 
mitted to the following tests before it is passed for use :— 
1. It is placed in a cramping machine for 15 hours, to ascertain if 
it is of the proper temper. If too hard it would break, if too soft it 
would become reduced in length. 
2. It is subjected to a weight of 40 lbs., which reduces it to a 
length of 1 in. from If ins., and which is 3 lbs. more than it has to bear 
when at "full cock" in the gun. 
3. It is placed in a machine, and undergoes the strain and motion of 
firing 500 rounds. 
The spiral spring was supposed to be a weak element in the Martini 
lock; but when thus tested it stands its work remarkably well, and 
even if it does become unserviceable it can be replaced with great ease. 
The Striker is also of tempered steel. When made, the point is, as a 
test, hammered through a sheet of copper several times, to ascertain 
that it will neither break nor bend in actual use when striking the 
copper cap in the base of the cartridge. It also can be easily replaced 
if necessary. 
Action. —The lever, on being pulled up, not only raises the block so as 
to close the breech, but in doing so compresses the spiral spring to full 
