312 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[OcTOBEB, 



15. The EccKntric Sheet Metal and Wire Gage. 

 Roberts, of Manchester. 



By Mr. Ricuabd 



The g.ige is thus constructed: — A plate of brass, about if inches 

 diameter and i-inch thick, is recessed on the upper side to the 

 de]ith of g-inch and l inches diameter, leaving a margin -nT-i'ich 

 broad. In the centre of tlie recess is a hole into whicli is fitted a 

 steel pivot wliose upper end is rivetted into a steel disc 3-S inches 

 diameter and -Jj-inch thick; the pivot is eccentric to the disc -J^th 

 of an inch, and conseciuently one point in the periphery of the disc 

 touches the inner edge of the brass margin, with which the top of 

 the disc is level. To the under side of the brass plate a small slide 

 is fitted, to the outer end of which a piece of steel is attaclied (by 

 screws), that passes up through a notch in the brass margin about 

 i-inch, and forms the inner or sliding jaw of the gage : the outer 

 jaw is formed of a similar, piece of steel also passed through the 



notch in the brass margin, and is secured to the brass plate by 

 screws. The inner edge of the sliding jaw is rounded to a radius 

 of ^inch, and is kept in contact with the periphery of the eccen- 

 tric disc by a spring (under the disc), which acts against a stud in 

 the slide projecting through the brass plate. The margin of the 

 brass plate is divided through one-fourth of its circumference, com- 

 mencing at the centre of the sliding jaw, into 75 equal parts, which 

 are numliered decimally. The extremity of the disc is then set at 

 zero on the scale, and the jaws accurately adjusted to touch each 

 other, after whicli the extremity of the disc is turned to the fifth 

 division, and a line is made on the disc to corresi)ond with zero on 

 the scale, at which point the jaws will be opened a little. The 

 disc is turned to the required gage number by means of a milled 

 button, or by two studs, and is fixed there by a milled nut on the 

 end of the pivot below. 



It mav be convenient to have the mimhers extended from 75 on 

 a fourth of the circumference, and to 100 on a third, but the law 

 of increase in the figures beyond 70 would be reversed. It will be 

 obvious that gages having different numbers and dimensions may be 

 more suitable for certain descriptions of work, and likewise that 

 the eccentric principle may be applied to gages in many various 

 ways. 



This gage possesses the following properties : — 



l.st. A corresponding gage may be made without expensive tools 

 from a written description of the means employed to make the 

 original. 



2nd. It admits of accurate construction and easy re-adjustment. 



3rd. Eacli succeeding number being larger than the preceding in 

 a progressively increasing ratio, adapts the gage equally well for 

 high and low numbers. 



1 6. On Hosmer's Self-Acting House Cistern. 



Mr. Wood read this paper, and exhibited a model of the appa- 

 ratus. It consists of two separate divisions (A, B), in the same 

 cistern, the larger division being for domestic purposes, the other 

 for cleansing the drains and sewers. There is a two-way inlet- 



Fig. I.— Self-Discharying House Cistern. 



cock C, with b.nll and lever, one aperture opening into the small, 

 the other into the larire division. The water from the main being 

 turned on, the small divisi(m B, of tlie cistern becoming first filled, 

 flows over into the other A; the water rising in A, lifts the ball 

 and lever, until stopped by the pressure of the fluid column upon 

 a valve at the bottom of the small division B, with which it is con- 

 nected by a chain. The water continuing to rise, the ball becomes 

 nearly immersed, when its superior buoyancy overcoming the pres- 

 sure upon the valve, lifts the latter suddenly to such a height as to 

 allow of a free flow through a large syphon-trapped pii)e into the 

 drain. The larger division of the cistern becoming filled, is re- 

 tained for domestic purposes. 



Fi'-', 2.- Self. Discharging Slreet Tank. 

 The above taaks are In use in the City of London, by order of the Court of Sewers. 



