366 Notices of Books. [July, 
IV. The cascable is first forged from the best scrap iron 
into an oblong block, then turned cylindrical and a bevel 
thread cut on it; the button is turned on it, and a hole 
is drilled through one end for the purpose of screwing it into 
the gun. 
All the parts are now ready for building up. 
First the B tube is shrunk over the muzzle of the A tube, and 
the A and B tubes shrunk up are placed together in a lathe, and 
they are fine-turned to receive the jacket. 
The half-formed gun being placed standing on its muzzle 
in the shrinking pit, the jacket is heated and shrunk on, and 
allowed to cool naturally, a jet of water playing up the bore 
to keep the interior cool. 
The cascable is next screwed in, an operation which it may 
be imagined requires great care, for the front of it must bear 
evenly against the end of the steel barrel. One round of thread 
is turned off the end of the cascable, so that there may be 
an annular space there, which in connection with a channel now 
cut along the cascable and across the thread, will form a gas- 
escape or tell-tale hole in case the steel barrel should split at the 
end. Various finishing processes are next proceeded with pre- 
vious to proof, which we need only enumerate, viz., fine-boring, 
second rough cutting of chamber, finished boring, broaching of 
bore and finishing chamber, lapping, rifling, and temporary 
venting. The manufacture of the higher natures of guns are 
on the same principle, and the only difference is in having 
extra coils. All guns are minutely examined before proof, 
and gutta-percha impressions are taken of the whole length 
of the bore in four quarters. The bore of all guns of g-inch 
calibre and upwards is also accurately gauged every 3 inches. 
The proof is based on the highest charge which the gun will 
fire on service, viz., two rounds of 14, the highest battering 
charge and service projectiles; this will not improbably be 
altered to the highest service charge with heavier projectiles. 
After proof the guns are again tested by the water being 
pumped at high pressure into the bore, and gutta-percha im- 
pressions again taken and the bores gauged. If there should be 
any doubt about a slight defect the gun is again subjected to five 
more rounds, and if after that the defect does not appear to 
increase the gun is passed. 
The last chapter treats of the important duties of examining, 
testing, and preserving guns, &c., as to their defects and 
repairs, &c. 
Finally, in a valuable Appendix, are given range tables and 
fuze scales and other useful information. 
We can only conclude by remarking that nothing could be 
more opportune at the present time than the appearance of this 
compendious and satisfactory text-book. 
