Part 21 (2/2)

The entire apparatus of thetihtthe rails laid down upon the timber way The same boiler that supplied the steam haine fixed to the platfor the next pile which had to be driven The steam was conveyed to the haraving The pipe accommodated itself to any elevation or descent of the hauide box, supported by the shoulders of the pile, a to seven tons in all, rested upon the shoulders of the pile as a ”persuader;” and the eighty blows per y upon the top of the pile head No soil, that piles could penetrate, could resist such effective agencies

[Iraram of the Steam Pile-Driver--The chief feature of novelty of this pile-driving machine consists in the employiving agent, and also in the ht of the entire apparatus, consisting of the hauide-case B, is eetic blows of the steam hammer These ponderous parts rest on the shoulders of the pile H all the while it is being driven, the pile in this respect being the only support of the apparatus A B C

So that, besides the eighty blows per etically deals out to the head of the pile froht of the apparatus constantly acts as aof the pile into the ground; the hoisting chain D being let slack the while, so as to allow A B C to ”follon” the pile H, while the eighty blows per minute are incessantly showered on its head The upward stroke of the piston, with its attached haht not only by allowing the steam that raised it to escape, but as soon as the piston passes the escape holes X X, the confined air above the piston at O rebounds, and so aids y of the fall of the hareat deal of curiosity in the dockyard as to the action of the new ood-natured challenge to vie with the down a pile They adopted the old ers sought out two great pile logs of equal size and length--70 feet long and 18 inches square At a given signal we started together

I let in the steaan to work The four-ton block showered down blows at the rate of eighty a minute; and in the course of four and a half minutesat the ordinary un to drive It took the of their pile!

Such a saving of time in the performance of similar work--by steam versus manual labour--had never before been witnessed

The energetic action of the steah up aloft, and following it suddenly down, the rapidly ha out of ”the waste steaht When uide case were speedily re-hoisted by the s and locomotive work of the machine; the steam hammer portion of which was then lowered on to the shoulders of the next pile in succession Again it set to work

At this the spectators crowding about in boats, pronounced their approval in the usual British style of ”three cheers!”

My new pile-driver was thus acknowledged as another triumphant proof of the power of steareat ere speedily driven in

The as constructed, and the docks were completed in an unusually short time The success of my pile-driver was followed by nu the ie at Newcastle, the great Border Bridge at Berwick-upon-tweed, the Docks at Tynemouth, the Docks at Birkenhead, the Docks at Grie at Kief in Russia, the bridge at Petersburg, the forts at Cronstadt, the Ee of the Nile, at Yokohama in japan, and at other places

It enabled a solid foundation to be laid for the enormous superstructures erected over them, and thus contributed to the pers

The mechanical principles on which the efficiency of the steam pile-driver chiefly depends are as siinal The shoulder of the pile acts as the sole supporter of the ponderous uide-box This heavy weight acts as a predisposing agency to force the pile dohile the hty blows the ht into full action I am not aware of any other machine in which such a combination of mechanical forces is employed

Another very effective detail consisted in e the waste stea as a buffer to resist any undue length of the upward stroke of the piston

But for this the cylinder covers ht have been knocked off

The elastic buffer of waste steam also acted as a help to the doard blow of the haements form--if I may be allowed to say so--a happy illustration of ,” the application of co-up steam pipe hich the steahts, and the way in which the folding joints accoht of the cylinder, was another of hts In fact, this invention, like hts

The machine in its entirety was the result of a nuht in At all events, this most effective and novel machine was a special favourite withthis branch ofhad before been conducted on what I ht term the artillery or cannon-ball principle A small mass of iron was drawn slowly up, and suddenly let down on the head of the pile at a high velocity This was destructive, not impulsive action Someti it into the soil; in many cases the head of the pile was shattered into matches, and this in spite of a hoop of iron about it to keep the layers of wood together Yet the whole was soon beat into a sort of brush

Indeed, a great portion of the ”

the piles On the contrary, I ereat mass and moderate velocity The fall of the steam hahty blows the minute, and the soil into which the pile was driven never had tirip or thrust it up-- an impediment well known to ordinary pile-drivers At the end of the driving by my steam hammer, the top of the pile was always found neat and san

I ain revert to my intervieith the Lords of the Ad the at the hotel where they usually took up their quarters whiletheir annual visitation of the dockyard I was honoured with an invitation to confer with Sir George cockburn, Mr Sidney Herbert, and Captain Brandreth on a subject of considerable i of chain cables and anchors required for the Royal Navy The question was mooted as to whether or not some permanent injury was done to both by the test strains to which they were sub put on board shi+p This was a subject of vital importance The members of the Board requested me to act as one of a coratified by the invitation and gladly accepted it

On discussing the subject with these gentlee cockburn entertained an ingenious theory in support of his apprehensions as the effect of ”over-proof” straining of cables and anchors It was that they were originally in the condition of a stronghih he ht perform the feat, it was at the cost of a perht never be able to lift the saard to flesh and bone structures, was scarcely true with respect to encies I proposed a simple experiment with chain cables, which, it occurred to me, would show quite a different result--na the severest proof-strain would rise rather than fall at each successive proof of the same chain cable

To test the correctness of my supposition, we had a first-class chain cable put into the proof ain and again, until at last it was divided al strain kept rising and rising as each successive re that no injury to the natural tenacity of the chain had resulted from the increased proofs to which it had been subjected, and that the last broken links had beenthan the first The same class of deht-iron work used in the service

The Adratified with the result, as rehtened, no doubt, by the suggestions that had been made to the Adh in itself, but produced perhest iron

My syste was, in fact, another exemplification of the ”Survival of the Fittest”!

A very interesting truth came out in the course of our experiments

It was that the chief cause of failure in the links of chain cables arose, not so much from their want of tenacity, or fro in the et at this truth, many excellent cables as received froreat shi+ps riding at anchor in terrible gales, were pulled asunder link by link by an intentional destructive strain by the proving machine