L O C L C 751 any height. In fig. 24 the bolt has been shot, and the sliders carried forward with it. Just before they leave the tumblers they are received by the two small teeth C, C on the frame of the lock, holding each slider at whatever height it may then be ; those teeth go right down to the thin part of the bolt or as deep as the sum of all the tumblers and sliders. In this figure the topmost slider is received at its third notch, and each of those below it at some other notch. The tumblers having fallen behind all the stumps, the sliders cannot move until the tumblers are all raised again to the various heights at which they left them, which is possible only by the key that locked the lock. These locks have Hobb.s s protector behind the bolt ; ana the bit which moves the bolt is behind a revolving curtain (the darkest circle) which is kept steady by one of the tumblers resting on its flattened top. The bellies of the tumblers are shortened, to obviate a certain trick by which one of XewelTs locks was picked, but which it is not necessary now to explain. So far as we can judge, this lock has more than all the advantages of that, as it is much less complicated and liable to get out of order from any cause except that to which all locks with spring tumblers are liable, viz., from two tumblers getting stuck together by dirt, so that one of them rises too high with its neighbour. Oiling tumblers is accordingly fatal to them, though it is necessary in other part-s of a lock. The keys of these locks are practically made not of distinct bits screwed into a key frame as in fig. 22, which is the plan used in the Day & Xewell lock, and makes a heavy thing to carry, but separate webs are made, each complete in itself, and fitting into a thickish key pipe which need not be carried about. You may leave it near the safe, and lock up therein, or keep somewhere else, all the bits except the one you use for the day, and carry that in your waistcoat pocket. For such a lock as that described you may have as many of the sixty million bits as you like, and may get new ones from time to time. Or you may have separate bits, as in the parautoptic lock, but in that case you must take good care of the key whenever the lock is shut. The risk of tumblers sticking together in a changeable lock, or any other, may be obviated by not using springs but putting thin plates between the tumblers, as in Sir E. Beckett s lock, giving the tumblers tails coming down on the right of the keyhole in figs. 23, 24, and making the revolving curtain act on all the tails just before the key comes out, by means of an intermediate lever, or else by a small handle which might at the same time bring an escutcheon or external curtain over the keyhole. Yale Loci". This American lock is remarkable for the smallness of its key, shown from k to a in fig. 25, full size, and is a thin flat piece of steel weighing only -1 of an ounce. The narrowness of the keyhole would be an impediment to intro ducing a picking in strument together with any other in tended at the same time to give a twist ing pressure to the small barrel abc, which has to turn, as in the Bramah lock, in order to move the fl bolt, which is not shown in these figures. That may be done either as in Bramah Fig. 25. locks or by a tongue or bit attached to the end ab of the barrel as in several other locks. The barrel is prevented from being turned, except by the proper key, thus. The (apparently) five plugs with spiral springs over them in fig. 25 are really all divided at the cross line be, being all now lifted to the proper height by the key. Conse quently the barrel abc can turn round, as there is no plug either projecting from it or projecting into it. But when the key is out, all the plugs are pushed down by the springs, and so the upper ones descend into the barrel and hold it fast. And again, if any of the steps of a false key are too high, some of the lower plugs will be pushed up beyond the barrel into the holes above them, and so the barrel cannot turn. The bevelled end of the key near a enables it to be pushed in under the plugs, though with some friction and resistance. It does not appear, however, to be any more secure than the Bramah lock, except by virtue of the smallness of its keyhole. Nor is the flatness and thinness of the key of any particular value on a bunch of keys, though very convenient for a single latch key to be carried in the waistcoat pocket, as extreme security is not requisite for latch locks. Yale Time Lock. The same company have an entirely different kind of lock from all the preceding ones ; it consists of a watch in a case enclosed within the safe door, and has a dial with pins marked for every hour, something like a "tell-tale clock." Any number of these pins can be pulled out a little, and the watch will let a weighted lever fall against the bolts of the safe during all those hours, ani hold it up during all the other hours, or vice versa. For security the case contains two such watches, so that one may do the work if the other happens to fail. Thus no key is used (except the watch key for winding), but the safe can be opened by a handle moving its bolts at such hours as the watch is set for, and at no other. It should be added that Mr Hobbs introduced into England in 1851 the American system of manufacturing every part of a lock by machinery, so that all similar locks of a given size are exactly alike, except the keys, and the gating in the tumblers, which is cut when they are lifted by the key ; and even those are done by machinery adjustable to secure what may be called an infinite number of varia tions. The same system has been adopted in the Government rifle manufactories, and for clocks and watches ; and no hand-work can compete with it. (E. B.) LOCKE, JOHN (1632-1704). Some idea of the man and his surroundings is more needed for the interpretation of what Locke has written than in the case of most philosophers. His youth was spent amidst the war of principles of which England was the scene in the middle of the 17th century. In later life he mixed much with the chief actors in the political drama that followed the Restoration. In his advanced years he was the intel lectual representative of tendencies which at the Revolution settlement inaugurated the tranquil material progress and tolerant but more prosaic spirit of the 18th century in England. It is instructive to see how the foundations of belief and the constitution of knowledge are investigated by an English gentleman, who was no recluse mediaeval monk or pedantic modern professor, but a man of the world, practically conversant with affairs, in tone calm and rational, and now justly regarded as the typical English philosopher. Locke was born in the county of Somerset, on the 29th of August 1632, six years after the death of Bacon, and three months before the birth of Spinoza. His father was a small landowner and attorney at Pensford, near the northern boundary of the county, to which neighbourhood the family had migrated from Dorsetshire early in the century. The elder Locke, a strict but genial Puritan, by whom the son was carefully educated at home, was engaged in the military service of the popular party when the son was a boy, Bristol being one of the centres of the war. " From the time that I knew anything," Locke wrote in 1660, "I found myself in a storm which has continued to this time." For fourteen years his education was going on at home, in the Puritan family. The house at Beluton, on his father s little estate, in which these years were spent, may still be seen on the side of one of the orchard-clad vales of Somerset, half a mile from the market- town of Pensford, and 6 miles from Bristol. The actual place of Locke s birth was atWrington, 10 miles westward, in a house which still exists, where his mother chanced to be on a visit.
