Messrs. Bramah are well entitled to offer any explanation concerning the relative perfection of the lock in question, and of one that they could now produce with certain improvements in some parts of the working mechanism; but if these improvements do not involve any new invention, patented or otherwise,—that is, if the lock be really a carrying out of the contrivances already made public,—it is difficult to see why it should not yield to the same treatment as the other. It is true that, shortly after the decision of the arbitrators, Messrs. Bramah exhibited a new lock in their window, and repeated their challenge in the same terms as before, with the single addition, that applications were to be made in writing only. We have reason to know that an application was made, and that the consequence was the withdrawal of the challenge. In respect to the actual contest, however, the character and position of the arbitrators ought surely to hold Mr. Hobbs justified in his proceedings. They were not all Americans (supposing nationality to give a bias in the matter); two were Englishmen, both of distinguished rank in respect to mechanical knowledge; and as Mr. Hobbs was as much bound by their decision as Messrs. Bramah, he was entitled to claim any advantage resulting from a favourable decision.
The following is a description, so far as can be given in words, of the mode in which Mr. Hobbs operated on the Bramah lock. The first point to be attained was to free the sliders from the pressure of the spiral spring; the spring was very powerful, pressing with a force of between 30 and 40 lbs.; and until this was counteracted, the sliders could not be readily moved in their grooves. A thin steel rod, drilled at one end, and having two long projecting teeth, was introduced into the key-hole and pressed against the circular disc between the heads of the sliders; the disc and spring were pressed as far as they would go. In order to retain them in this position, a curved stanchion was screwed into the side of the boards surrounding the lock, and the end brought to press upon the steel rod, a thumb-screw passing through the drilled portion of the instrument and keeping it in its place. The sliders being thus freed from the action of the spring, operations commenced for ascertaining their proper relative positions. A plain steel needle, with a moderately fine point, was used for pushing in the sliders; while another with a small hook at the end, something like a crochet-needle, was used for drawing them back when pushed too far. By gently feeling along the edge of the slider, the notch was found and adjusted, and its exact position was then accurately measured by means of a thin and narrow plate of brass, the measurements being recorded on the brass for future reference. The operator was thus enabled, by this record, to commence each morning’s work at the point where he left off on the previous day. The lock having eighteen sliders, the process of finding the exact position of the notch in each was necessarily slow. Mr. Hobbs employed a small bent instrument to perform the part of the small lever or bit of the key; with this he kept constantly pressing on the cylinder which moved the bolt. He thus knew that if ever he got the slide-notches into the right place, the cylinder would rotate and the lock open. He could feel the varying resistance to which the sliders were subjected by this tendency of the cylinder to rotate; and he adjusted them one by one until the notch came opposite the steel plate. The false notches added, of course, much to his difficulty; for when he had partially rotated the cylinder by means of the false notches, he had to begin again to find out the true ones.
This description accords pretty nearly with that given in a former page; but we reproduce it here to shew not merely what might be the process adopted, but what really has been done. One circumstance ought at least to be noted in these transactions—there is no mystery; the method adopted is the result of a process of reasoning candidly and openly explained.
In justice to Messrs. Bramah we thought it our duty to give them an opportunity of stating what improvements they had made in their locks since the date of the Great Exhibition; and accordingly, on the 28th April, 1853, our publisher addressed to Messrs. Bramah a note, stating that a Rudimentary Treatise on the Construction of Locks was being prepared, and inviting them to contribute thereto. The following is a copy of their reply:
“124 Piccadilly, May 2d, 1853.
“Sir,—Pressure of business has prevented our sending an earlier reply to your favour of the 28th ult.
“The lock on which Mr. Hobbs operated during the Great Exhibition had been made nearly forty years, and when taken to pieces the sliders were found to be in iron, instead of steel; and the key-hole of the lock being three times larger than it ought to have been, enabled the operator to fix down the spring of the lock, and yet leave himself ample space to turn and bend the sliders (being in iron) at pleasure. The barrel of the lock in which the sliders act, instead of being whole length from front to back of padlock, was not quite half its proper length; a serious oversight in the workman who put the lock together, as the barrel being short, the sliders were necessarily so, which diminished the number of notches in the sliders full one-half, and to that extent diminished the security of the lock, and increased the facility of the operator.
“We send for your inspection a box of guards, which will shew you the barrel and sliders of our Bramah lock. You will observe several notches in each slider, only one of which will turn on the locking-plate, the others being what are termed false, or security ones. These notches being cut only the exact width of the locking-plate, require the most perfect accuracy to carry each down to its proper distance. In the lock on which Mr. Hobbs operated, in addition to the sliders being so short, and only half the number of security-notches in each, the notch which passed round the locking-plate was found to be cut twice the width it ought to have been. The whole of these defects have been corrected since the Exhibition.
“We are, Sir, yours respectfully,
“Bramah and Co.
“per J. Smyth.