1806.] 



New Patents lately enrolled. 



53 



is incurred tlirough the operation of 

 countinsi the largei-, and adding tlie funis 

 of the fnialler vveisihts, which is an evil 

 entirely obviated by the fcales of the pa- 

 tent weitiliiiifi-apparatLis, fliewing the to- 

 tal weigiit on mere infpection. 



MR. MARTIN cawood's, (leeds,) fiif an 



Improvement in t/ie Manufa&iirinii, of 



Metallic Cockn for convei/ing audjiop- 



ping of Lii/uids. 



This invention is thus fet forth. In- 

 flead of cafting the cocks of brafs, which 

 is the ufual practice, Mr. C. calls thcin of 

 iron, and faces, plates, bullies, or covers 

 them with brafs or bell-metal, or fuch like 

 metal, or compolitiou of metals, thofe 

 parts of the pillon and cylinder which 

 come in contai^t with each other when 

 the cock is in ufe. This facing is to be 

 faftened on by cementing, tinning, fol- 

 dering, or brazing ; and the pifton and 

 cylinders are fitted with each other in the 

 ufual way. 



Obfcrvatiom. — The common compofi- 

 ■tion for brafs cocks (a«iixture of copper 

 and lead,) is found to be unfit to refiftthe 

 extremes of heated fleam and a cold frof- 

 t_y atmofphere ; but cocks plated in the 

 manner here propofed, viz., with good 

 foft iron, are found to ftand better than 

 any other metal the extremes of heat and 

 cold. Hence lleam-cylinders and hot- 

 water pumps for engines are now made 

 ■wholly of that metal. The metal a!fo 

 with which the pifton and cylinder of thcfe 

 cocks are plated, being of irnail weight, 

 it may be made of fuch fuperior quality, 

 that the objctbtions made againit com.mon 

 rock-metal cannot apply to this mix- 

 ture. 



Common cocks, when out of repair, 

 are in general fold as old metal ; for 

 when they are ground two or three times, 

 the hole ii> the pifton is lb low in the cy- 

 linder, that it will not admit a fufficient 

 quantity ofHuid equal to the hereof the 

 cock ; but in tlicfo plated cocks, when 

 the pifto is worn too low, the pifton or 

 cyhiider can be plated at a trifling exr 

 pence, and the cocks rendered as good as 

 new. This in large cocks, for which this 

 invention is more efpeciaily adapted, will 

 1)6 a very great laving. 



The patentee allcrts, tliat cocks of all 

 Ciilibrcs, from a quarter of an inch up- 

 wards, made to fix on ail kinds of iron, 

 copper, or lead pipes, with fliinges or tin- 

 ned tails, may be had at his manufactory 

 at half the price of the comusoii brulk 

 cotki of euual bore. 



MR. trotter's, (sOHO-Sf>UAllF.,) for a 

 Rotarij Kngme for upplyitig the Pow- 

 ers of Fluids us firji Moverx. 

 This engine conlilts, 1. Of a circular 

 piece called an outer barrel ; 2. A circu- 

 lar piece called an inner barrel ; 3. A 

 circular piece called the eccentric ; 4. A 

 piece called the fweep, which fliuts com- 

 pletely acrofs the fpace between the out- 

 er and inner barrels, fo as to iiitcreept 

 the communication in that part ; 5. Cap« 

 or covers at each end of the faid pieces, 

 which dole the fpace between the two 

 barrels, and ferve, by grooves or other 

 fittings, to keep the othci- paits iu tlieir 

 refpective places. 



The fituations and motions of Uie parts 

 are thus defcribed. 1. The baiTcls are 

 concentric. — 2. I'he fwecp is capable of 

 moving or revolving tlirough tlw; fpace 

 bet\veen the barrels. It may be eitlier 

 feparate from the barrels, or it may be 

 fixed to either or both of theiii. It is lb 

 well fitted or fixed, that no lluid, or a verir 

 trifling quantity, fiiall pafs through tlie 

 places of its appofition or junction with 

 the barrels and caps. — 3. 'I'he eccentric 

 is of fuch a diameter, and fo wrought, 

 that its concave and convex furfaces ihaU 

 touch the inner and outer barrels, and 

 that tlic places of contact Ihall not aduut 

 any fluid to pafs between the eccentric 

 and each barrel. The eocentric is ca- 

 pable of rotation iu its own plane or pe- 

 riphery, but not othei-wilb with relation 

 to the caps ; and it has a long perforatioa 

 through which the fwcep is ipiit, confc- 

 quently the fwecp and the eccenU-ic will 

 always rnDve together. 



It may be pointed out as diftinguiihing 

 characters of the laid engine, that when- 

 ever the fivcep is moved, the fpace which 

 is comprehended between the barrels 

 and the eccentric, and the pollerior or 

 hinder furface of the fweep, will be conti- 

 nually enlarged ; and that the fpace 

 which is in like manner compreliended 

 between the barrels and the eccentric, 

 and tl;e anterior or fore furface of the 

 fweep, will be continually diminiilied ; 

 excepting that fooii after the fv^ eep has 

 paifed at or near the places of conta6t be- 

 tween the eccentric and th-e outer b>trrels, 

 the pofterior fpace will be fuddenly dimi- 

 nilhed by the feparation of all that por- 

 tion thereof which was comprehended 

 between the eccentric and the outer bar- 

 rel, in confequence or by reafon of the 

 faid place of contact having come to be 

 behiiid the fvveep. And alfo, that fo(;n 



aftei: 



