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and the key, beinfr forced down into the key-hole H, de- by prefling down any one Aider of the depth at which the 

 preffes all the Aiders at once, until the projefting leaf / of notch in it will be oppofite the fteel rinjr. Another great ad- 

 vantage of thefe locks is, that from the circumrtance before 



the key ilops upon the bottom of the recefs .r, cut in tbe 

 upper edge of the barrel. In this polition the Aiders are de- 

 prefied, fo that the notch r made in each Aider comes 

 exaclly oppofite the fteel ring bb, and the barrel is a{ liberty 

 to turn round all the Aiders, being by this means removed, 

 or at leaft relieved, from the fteel ring, which, as before 

 mentioned, embraces a groove cut round the barrel, but 

 which cannot turn round therein unlefs the Aiders are alfo 

 moved by the key, that the notches cut in them coincide 

 with the groove cut round the barrel, and then it can turn 

 freeiv round.. The key, having thus reheved the barrel by be- 

 ing thruft in as far as it can go, obtains a hold of the barrel to 

 turn it round, by the leaf / entering the recefs x, which it 

 exaclly fills up, fo as to form a continuation of the cir- 

 cular top of the barrel : but as foon as the key is turned 

 round with the barrel a fmall quantity, its leaf is caue^ht be- 

 neath the circular cavity in the top of the box D, and 

 thus the key is prevented from being thrown out by the 

 fpiral fpring ■o', until it has been turned quite round, and 

 locked or unlocked the bolt : then the leaf of the key coming 

 oppofite the enlargement c, Jig. i, of the key-hole H, the 

 fpring throws the key out and raifes all the Aiders, that they 

 may interlock with the fteel plate b b, and prevent the barrel 

 from turning, unlefs the key is again put in, (its leaf being 

 oppoiite the aperture a of the key-hole, ) and being thruft 

 forwards as far as it will go, the barrel will turn round very 

 eafily ; and when it has made a complete circuit, the lock is 

 opened, and the key thrown out of the key-hole by the 



The fecurity of this ingenious lock from being picked, or 

 opened by a falfe key, depends upon a circumPcance not 

 yet mentioned, which i?, that the notches in the fix Aiders are 

 io made, that every one requires to be depreffed a different 

 quantity to bring them all at once oppofite the fteel ring, in 

 which pofition alone the barrel can be moved. For this reafon 

 the fix notches in the key are all of different depths, corre- 

 fpondent to the pofitions of the notches in their refpeftive 

 fliders ; and unleis each notch in the key is of the proper 

 depth, the lock cannot be opened, for any one being too 

 deep, that Aider will not be preffed low enough to relieve 

 the barrel, and will hold it fall, though all the others may 

 be correct : on the other hand, any notch not being of fuffi- 

 cient depth, the Aider it acts upon will be preffed too far, 

 and in this cafe the notch in it, having paffed by the fteel ring, 

 ■will lock the barrel as effectually as though it was not far 

 enough. Thus this lock admits of an immenfe number of com- 

 binations ; I ft, in the number of the Aiders ; 2dly , the depths 

 of the different notches in the key ; and 3dly, the arrange- 

 ment of thefe Aiders. The combination of thefe three changes 

 admits fuch an immenfe number of varieties of locks, that it 

 never need happen that two locks fhould be made to open by 

 the fame key Any of Mr. Bramah's locks may be arranged 

 fo as to require a new and different key in cafe the original 

 fiiould be loft or llolen : for this purpofe the lock mull be 

 opened, and the Aiders taken out and changed into different 

 grooves : a new kfey muft now be made, with the grooves of 

 the fame depth of the original key, but arranged in a dif- 

 ferent order, correfponding with the new arrangement of 

 t!ie Aiders. The old key will not now open the lock. 



To pick a lock of this kind is perhaps impoffible ; becaufe, 

 though the Aiders are expofed to the examination of any per- 

 fon, yet no information can be obtained of the depth of each 

 of the Aiders required to be depreffed ; for, unlefs they 

 are all together preffed down, the barrel cannot be turned 



explained, of the bolt having no adlion to turn the barrel, 

 though the barrel has a great power to fhoot the boll, a 

 ftrong lock may have but a very fmall key. Forinftance, the 

 bolt of the lo^-k, in the plate which is drawn its fiiij fizc, 

 is of great ftrength, while the key R is fo fmall, that it 

 may always be carried fufpended to the watch chain, and 

 then it will not be in danger of being loft or miflaid, as one 

 may happen to lofe a key, and give oppcrtiinity for ill 

 difpoied perfons to make a falfe key from it, unknown to 

 the owner. 



ill the leaft, and without turning it, no guefs can be made 

 Vol. XXI. 



A lock invented by Mr. Stanfoury, an American gentle- 

 man, has great merit. To explain it, we muft fuppofe that a 

 flat circular plate is fitted to turn round upon the centre pin 

 for the key, and that this plate, when turned round, fiioots 

 the bolt, which may be done by various means. The lock- 

 ing part confifts of four, fix, or more fmall fteel pins, 

 which are received in holes made very near each other, 

 through both the circular turning plate, and the fixed plate 

 beneath it. By thefe pins the circular plate is held fall 

 from turning. The key has the fame number of pins, 

 and arranged in the fame pofition and diftance as the 

 pins in the plate. The key being introduced, it is preffed 

 forwards againft the circular plate, and turned round till the 

 pins in it come over the pins in the circular plate, and the 

 preffure of the hand forces the pins out of the circular plate, 

 the pins in the key occupying the place of them. The 

 plate is now relieved, and the key has hold of the plate to 

 turn it round and open the lock. Each pin is provir.L-d with a 

 fpring behind the fixed plate to force it forwards. The 

 difficulty of making a falfe key to this lock is very great ; 

 as any error in the number, fize, pofition, or length of the 

 pins, will prevent it from opening the lock. To avoid 

 the danger of i.mpreffions being taken, many marks are 

 llamped upon the circular plate, which are exactly the fame 

 at the marks of the real pins : thus an impreffion taken from 

 it would only miAead. 



Mr. Sts.nfbury has alfo made an ingenious improvement 

 upon the common fpring door-lock. The handle which opens 

 the fpring catch for fattening the door, inltead of requiring 

 to be turned round, is made fo that it withdraws the fpring 

 catch, by pulhing the handle on one fide of the door and 

 pulling it on the other. This method is extremely conve- 

 nient ; for prefTing the handle releafes the lock, and conti- 

 nuing the preffure opens the door, and pulling the handle on 

 the other fide has the fame effect. A perfon with his hands 

 full may open fuch a door by only leaning againft the 

 handle. 



Lock, or IVeir, in Inland Namgalion, the general name 

 for all thofe works of wood and Itone, made to confine and 

 raife the water of a river : the banks alfo which are made to 

 divert the courfe of the river, are called by thefe names in 

 fome places. But the term loch, or pound-lack, is more parti- 

 cularly appropriated to exprefs a contrivance, confiftingof two 

 gates, or pairs of gates, called the lock-gates, and a cham- 

 ber between, in which the water may be made to coincide 

 with the upper or lower canal, according as the upper or 

 lower gates communicating with it are opened ; by which 

 means boats are raifed or depreffed from one level or reach of 

 a canal to another. See Plats V . Canals. 



Lock of fCater, is the meafure equal to the content of 

 the chamber of the locks, by which the confumption of 

 water on a canal is cflimated. 



LocK-iaJ>er, a perfon who attends the locks to take 

 H h - care 



