Having now detailed as much of the “_modus operandi_,” as the patience of the reader will admit, I shall endeavour to give a peep into the “_sanctum sanctorum_” of the gun-makers’ workshop. I have shown in detail what course ought to be pursued in the construction of guns of the best quality only; and before proceeding further shall finish this part of the subject. I am not, as some would say, “going to expose the _whole_ secrets of the trade:” oh no, only a portion. There are six qualities or varieties of mixtures of iron for barrels of best quality. The plate-facing contains two kinds finished, composed of steel entirely, but of different degrees of carbonization; one is composed entirely of a laminated series containing many scores of distinct laminæ in the thickness of the sides of the barrels, twisted and beat into tortuous shapes. The other, of larger laminæ, but showing the edges of the laminæ at an angle with the length, and thus appearing larger than, if presenting the side or end of the plates. Care must be taken that the great proportion of the fibres shall always run round the tube, so that the greatest portion of strength may be obtained, together with a beautiful figure. The cost of this arrangement is considerable, as it involves a great waste of metal, and occupies a considerable time to work and re-work--twisting, faggoting with the bars placed in various forms, at acute angles to each other, at right angles, plaiting three or four rods together, as a lady does her hair, cutting these into pieces, faggoting and welding them into one, and, in short, undergoing an endless routine of manipulations, which it would be strictly unprofitable to detail, but are all productive of cost. An ingenious man may work and improve metal of this nature until its cost equals the price of silver; and, if judiciously done, improving it still, even until he has wasted 90 per cent. of the original material. The ultimate characteristics and properties of iron have, as yet, never been ascertained: it is capable of being condensed until it becomes nearly, if not quite, equal to the specific gravity of silver or lead. No pursuit, mechanical or philosophical, presents so great and so beneficial a research, to the whole civilized and scientific world, as iron. I could twist and retwist iron, until, from the beautiful and interesting results, it would become with me a sort of monomania. I wonder not at the variety of patterns in a Damascus sword-blade: the mind conveys me to the scene, and a regret arises that I did not live in those times; yet still it is but a mechanical arrangement directed by an ingenious mind, and the ultimate benefit, apart from the beauty, is more than imaginary. However, it proves that the Orientals were artists, and that they were appreciated: were this the case now with us, we could do all they ever did, and more.