1849.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



.307 



stubs, is due to the late Mr. Adnms, of AVednesbury, who, twenty 

 years ago, introduced what is yet termed Damascus iron, which is 

 constructed of alternate layers of steel and iron, fan;goted, drawn 

 down into rods, .and then twisted; and when welded into barrels, 

 forms the beautiful Damascene barrel. The success of this expe- 

 riment, not only in point of beauty but of strength, was so great 

 as to he under-estimated at an increase of 50 per cent, compared 

 with the strength of stub-twist iron. 



The next improvement was to blend more intimately steel with 

 the horse-nail stubs, in the proportion of one to two of the latter. 

 This was effected by cutting scrap-steel into pieces, assimilating 

 with the stubs very carefully, cleaning them, and then welding into 

 a bloom, and rolling. The fibrous system seemed in this case to be 

 more perfect, for though possessing less steel in its composition, 

 yet it was quite equal in tenacity. The difficulty in obtaining old 

 stubs of quality sufficiently good, arising from deterioration in the 

 original iron, has rendered the manufacture of this variety nearly 

 obsolete, or, in cases where it is yet produced, the quality is so 

 inferior as scarcely to rank third in quality. 



The next and most important improvement in metals is the ma- 

 nufacture of gun-barrels from scrap-steel entirely, and for this 

 purpose old coach-springs are generally in request. By clipping 

 these into pieces, perfectly cleansing them, and then welding in an 

 air-furnace, a metal is produced which surpasses in tenacity, te- 

 nuity, and density, any fibrous metal before produced. The tena- 

 city of it when subjected to tension in a chain-testing machine is 

 as 8 to 24 over that of the old stub-twist mixture. The perfect 

 safety of barrels produced from it is astonishing. No gunpowder 

 yet tried has power to burst them when properly manufactured. 



The progressive value attached to these various metals has in- 

 duced Mr. Greener to try experiments on a more extended scale. 

 To effect this he takes ingots of cast-steel, from the mildest made 

 to No. 3 in the scale of carbonization; these after being roUed into 

 flat bars, are to be clipped into small pieces, intimately mixed, and 

 welded, as before, in an air-furnace; drawn dovin in tlie rolls, re- 

 faggotted, again drawn down, and then converted into gun-barrels, 

 either with or without spirally twisting them to form the Damascene 

 figure. Barrels made from this (which he terms laminated steel) 

 are in reality perfectly safe. To ascertain this, breeches were 

 screwed into both ends of a gun-barrel more than ordinarily light; 

 eight drachms of gunpowder (or three ordinary charges) were then 

 introduced; the breech was screwed in again, and the powder fired 

 through an orifice the size usually found in gun-nipples. The 

 density and tenacity of the metal are sufficiently great effectually 

 to resist the enormous force of this great charge of powder, the 

 exploding fluid passing through the nipple like steam from a safety- 

 valve. The principle here developed is the perfection of the 

 fibrous system with increased density of metal. The dissimilar 

 carbonization of the metals forms dissimilar fibres when thus enor- 

 mously extended, with a complete absence of any crystalline struc- 

 ture in the metal, — the existence of which in any material, either 

 gun-barrels or any other manufacture which become subject to 

 violent concussions, explosions, or blows, may safely be set down as 

 of the negative kind. 



Swords are another manufacture to which this improvement es- 

 pecially applies. i\Ir. Greener observed tliat all his investigations 

 go to fully satisfy him that it is in a similar way the Arabs produce 

 their finely-tempered Damascus swords — namely, using two steels 

 of different carbonization, mi.xing them in the most intimate man- 

 ner, and twisting them many fantastic ways, but observing method 

 in that fancy. He is led to think that they do not temper by 

 heating, and immersing the blades in a cooling liquid, as practised 

 by us at the present day. If we subject a Damascus blade to the 

 action of acid, the laminated structure is perfectly visible: if the 

 blade be heated and immersed, crystallization takes place, and the 

 lamina disappears for ever. He was not then going to discuss the 

 merits of our mode of tempering swords, but would merely allude 

 to the fact that no European weapon had ever yet been produced 

 equal in tenacity to those of Damascus. 



The government inspector of small arms gave in evidence before 

 a committee of the House of Commons in May last, "that the 

 swords manufactured in Birmingham were not fit to be issued to 

 the army." If so, this question becomes of vital importance not 

 only to that district, but to the whole empire. Mr. Greener's in- 

 vestigations satisfied him that tempering by crystallising the steel 

 (i.e. tempering in the ordinary way) is fer from the wisest course. 

 He has found by experiment that the Damascus blade in its fibrous 

 state, or hammer-hardened, is more difficult to break by 100 per 

 cent, than the best English-made blade: but temper it in the same 

 way, and it shows no greater tenacity than our own. The Damas- 

 cene figure is destroyed by the carbon becoming equally diffuse; 



nor will acid develope it — it is entirely gone. But oTiserve it witli 

 a glass attentively, and what is now a mere mass of crystal was 

 previously a fibrous system of the most minute and beautiful ar- 

 rangement. The tendency of all crystalline structures to lose 

 tenuity, and separate by repeated actions of the waves of vibration, 

 is evident to all scientific men. From these facts we may draw the 

 conclusion, that swords constructed of dissimilar steels, tempered 

 by condensation of its fibres, either by repeated rollings, hammer- 

 ing, or many other processes which our perfect machinery give us 

 the opportunity of doing. Thus we may hope to see ever)' soldier 

 of the empire armed with a weapon as good, if not so costly, as the 

 highly-prized Damascene. 



Lastly, tlibugh not of least importance at the present day, is the 

 construction of railway axles. If experience shows that the addi- 

 tion of one-third steel to two of iron doubles the strength of a 

 mass so constructed, why not adopt this improvement in railway 

 axles and other parts of machinery on which the safety of hundreds 

 sometimes depend ? A few months previously to the death of the 

 late George Stephenson, Mr. Greener consulted him on the possi- 

 bility of improving this essential material, and at his instigation 

 proceeded to make a considerable number of experiments. It ap- 

 peared to him a settled fact, that from the affinity iron evinces for 

 the various gradations of electricity, to galvanic electricity maybe 

 traced the rapid crystallization which takes place in railway axles, 

 after having travelled over a given number of thousand miles. It 

 is well known to all acquainted with engineering, that axles con- 

 structed of the most fibrous homogeneous iron, are changed into a 

 crystalline state of the most perfect kind, extending some inches 

 from the journal. This, it may be assumed, is effected by the gal- 

 vanic electricity generated by the bearings and the journal while 

 in rapid motion. To this also, he apprehends, m.iy be attributed 

 the great tendency of axles to heat. To ascertain this fact, Mr. 

 Greener subjected wire of various metals, from the ordinary iron 

 wire to wire constructed of his laminated steel, to a strong and 

 lengthened current of electricity, for a period of two hours, which 

 effectually changed the fibre of the inferior irons to a crystalline 

 state, — their tenacity was entirely destroyed, and breaking with 

 the brittleness of glass. The highly fibrous state of both the mix- 

 tures of steel and iron, and the fibrous steel, was not affected in 

 the like ratio — not even after enduring the passage of the current 

 for double the period. Hence he inferred that mixtures of steel 

 and iron in axles woiild not only add to their durability and safety, 

 but materially lessen the consumption of the lubricating material. 

 This result will also be materially advanced by the adoption of a 

 hollow axle, — not hollow axles, which require increased diameter or 

 surface, but an a.xle of precisely the present dimensions, with a 

 perforation not exceeding ^-inch in diameter : but this is a question 

 of importance enough to demand a paper exclusively devoted to it. 



To the adoption of mixed steel and iron is attributed the suc- 

 cessful use of the gun-harpoon; for many years no iron could be 

 found which would effectually resist the rapid motion given to it by 

 gunpowder. It is a fact beyond dispute, that all gun-barrels will 

 only stand a cei'tain number of explosions: an ordinary iron barrel 

 will seldom stand a repetition of four pi-oofs, — and be their quality 

 even the best, a certain number of years' use changes their nature, 

 and they become unsafe. So it is with railw'ky axles, and, in short, 

 all structures of this metal, which, after a given time, part with 

 every quality that renders them valuable. And thus arises a ques- 

 tion whether the construction of horizontal bridges of iron is cal- 

 culated to endure the many years their projectors hope. The 

 waves of vibration, from the rapid passage of the locomotive, par- 

 takes much of the nature of concussion, and as such, is peculiarly 

 liable to be classed as one of those injured by excessive vibration. 



Remarks. — The President (Mr. Steplienson) remarked on the danger of 

 assuming facts and reasoning from that assumption. With respect to the 

 iufluence of vibration on the structure of iron, he considered there was good 

 room to doubt that the bearing force or pressure upon metals caused crys- 

 tallization. It was by no means proved that railway axles were subject to 

 the passage of currents of electricity, and therefore granting the assumption 

 that the passage of the electric current clianged the character of the iron, 

 there was a link wanting in the chain of reasoning, inasmuch as it was not 

 proved that axles were subject to this electrical influence. Moreover he was 

 inclined to doubt whether if a piece of iron was at first perfectly fibrous, 

 vibration would ever change the structure of the metal. The beams of 

 Cornish engines, for example, were subject to vast pressure ; they never 

 became crystallised ; the connecting-rod of a locomotive was subject to 

 great vibration, strain, and pressure, vibrating eight times a second when 

 the velocity is 40 miles an hour : he had watched the wear of a rod for 

 three years, and no change was perceptible in the structure of the iron. He 

 doubted, therefore, the correctness of the assumption made by Mr. Greener. 

 — After a few words from Mr. Roberts in support of this opinion, the dis- 

 cussion terminated. 



40* 



