Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 3, 1802).djvu/142

122&#93; 1 ■■] hoc jCd a pin, main-wjid, cross-ward, and step-ward or dap-ward : last- ly, the pin-hole corresponds with the hook-ward, main-cross-ward, shank, pot or beard, bow-ward and bit. The excellence of locks consists in the security they allbrd ; and as numberless schemes are continual- ly brought forward by designing rneu, to elude every contrivance of the most ingenious mechanics, the invention of a durable lock, so con- stru6ted as to render it impossible for any person to open its without proper key. Ins ever b.^en an ob- jeft of considerable importance. In the year 1/84, the Sociclij for the Encauragemeni of Arts, &c. conferrtd their silver medal on iSIr. TvYLOR, of Petworth, for his improvement on the latch or spring- bolls of common locks. This is cfFeifled by simply reversing the tumbler, so that its curved side a6ts against two stubs lixed on the tail of the latch, and thrusts back the latter with ease ; whether the knob be turned to the right or to the left, when the lock is opened. Mr. Taylor has al.-,o, brhind the tail of the latch, fixe.i a guide contain- ing a groove, in which runs a small friciion-n'heet, that serves to keep the latch in its direct situation, and at the same time to diminish its friifion : the arms of his tumbler are somewhat contracted, in order that the latcli or spring-bolt may move with gre.ater facility. By this construftion, the parts of the tumbler and latch, which are in coHta>St, move in a line, so tiiat they pass over the greatest space, undtr the smallest angle 3 and the lock itself may be constantly used for sevenil years, without requiring tlie appHcation of oil. The same Society also granted, LOG in the same year, the sum of ten guineas to Mr. Marshal, for a secret escutcheon, which, when fixed to a lock, may be so repeat- edly varied, that even the artist who made it, is unable to open the lock : as, however, ar satisfa<5tory description of its mechanism can- not be given, without the aid of en- gravings, we refer the reader to the 3d vol. of the Society's Transac- tions. Various patents have been obtain- ed for the construcVion of locks, so as to prevent the possibility of pick- ing them : the principal of these is JMr. Bramah's, registered in 1784; and Mr. Spkars's, in 1795 ; but, as the account of those inventions would be unintelligible without the aid of several engravings, the curi- ous reader will consult the 5th and 8th vols, of the Repertory of Arts and Maniifaclures, where they are minutely specified. Lock, in inland navigation, de- notes all such works (whether of wood or stone) which are intended to laise the water of a river; but it is more particularly applied to a kind of canal inclosed betweerj two gates, the upper of which is called a sluice-gate, and the lower a fiood-gate. These serve to conline the water, and thus to facilitate the passage of boats, both in ascending" and descending the canal. In the year 1/01, a patent was granted to Mr. James Playtair, architect, for his method of con- structing the locks of navigable ca- nals on a new principle, and also for improving such as are already erected. With this design, a cer- tain portion of water, in the ascent and descent of vessels, is conducted into reservoirs or cisterns commu- nicating with the lock upon dlffe- rcul