224

STATION-METERS.

outer hoods is sealed by the water alternately in the same manner as the inner hoods, andopened for the passage of the gas from them, by one constantly being above the water-line.In setting out the hoods, care must be taken to have them of a proper length. The directionin which the drum revolves is marked by the arrow over the top of the case.

The bevels of the division-plates d d are arranged so that they will enter the waterwithout effort. The axis a a, on which the drum revolves, is supported on friction-rollers.On the front end of this axis a spur-wheel S (Fig. 2) is fixed, working into another wheel T,having half the number of teeth ; at every half-revolution of the drum it will therefore makean entire revolution. The spindle of I passes through a stuffing-box, and is furnished at theopposite end with another wheel V, which marks 100 feet on the index. From a pinion onthe spindle of this last wheel another wheel is worked, having ten times the number of teethon the pinion, which will therefore mark thousands. This last wheel is again furnished witha pinion, and works into a third wheel, which will mark tens of thousands, and so on ; thequantities marked on the dials increasing in a tenfold ratio up to tens of millions, or higherif thought necessary.

The entire train of wheel-work is shown in the woodcut, Fig. 77, where a is the firstspur-wheel, working upon the main axis; b the second wheel, both being inside the meter-

case, and c is a wheel on the opposite endof the shaft of b, which projects through astuffing-box in the case, in order to com-municate motion to the train of wheel-workon the outside of the meter-case. Thewheel d, of the same size as c, drives the.hand which marks hundreds on the index,having a hundred teeth ; e, the pinion onthe wheel d, has ten teeth and drives thewheel/ that carries the hand which marksthousands on the index, having a hundredteeth; g, the pinion of the wheel f, drivesh, which marks tens of thousands on theindex, and in this manner any quantity maybe registered. If it be required to registerunits (and in smaller meters it is useful), the first wheel d is made to drive a pinion, p,having ten teeth, to the spindle of which the hand marking units is atttached.

The old contrivance of the “ Tell-tale ” when attached to the station-meter becomes avaluable instrument, as it serves the purpose of effectually pointing out every irregularitythat occurs in the production of gas during any hour of the twenty-four. Suppose, forexample, the superintendent desires to know whether his workmen have at any time duringthe day or night made the proper quantity of gas from the given quantity of coal. He mayupon examination find all the retorts in an excellent working state ; but whether they havebeen so at all hours, or whether the requisite quantity of gas has been really produced du-ring the time that the pipes which convey it into the mains have been open, is to him a

tens *»/\ thousand*thousand sY^. \