Kingdom.] KAIL WAY AND MARINE MECHANISM. 223

North Areas A. B. 10 to 34 ; C. D. E. 1 to 10, & 19 to 33 ; P. 1 to 32 ; G. H. 1 to 13, & 19 to 26.

"working the pit apparatus, and shutting off the steam atthe pit’s head. The figure represents the balance valves,and shows their method of action.

New self-reversing beam engine, for planing machinesand other purposes.

Silver locomotive and railway, with a new method ofreversing and of disconnecting locomotives and carriageswhen falling from the perpendicular.

Circulating steam boiler for generating steam at ex-perimental lectures.

New hydraulic locomotive for propulsion.

Horizontal water-wheel for large rivers, from 3 to 6 feetfall.

Self-acting valve cock without ground surfaces.

Gas water-meter, having a direct spindle which dis-penses with meter wheels ; index and stop-cock.

Highland shield.

101 Whytehead, W. K., Cornhitt —Proprietor.

1. McNaught’s steam-engine indicators, for measuringand recording pressures; used principally for ascertainingthe power and working order of steam-engines, for whichpurpose a communication is made between the cylinderof the engine and the cylinder of the indicator. Thevarying pressure of the steam acting on the piston ofthe indicator, raises or depresses the pencil in oppositionto the internal spiral spring, and registers itself on thepaper.

[To ascertain by this apparatus the pressure at variouspoints of the stroke of the engine, the paper is moved bya string attached to some working part of the engine, sothat its motion may coincide with that of the enginepiston. By the shape of the diagram thus traced, theexact power given out by the engine (as distinguishedfrom “ nominal power”), the most advantageous adjust-ment of the valves, the friction of the engine, the powerrequired by any portion of the machinery, the neglector attention of the engine-driver, and the friction of themachinery when using different oils, can be ascertained.The instrument is fitted with two springs and a doublescale, one for high-pressure steam divided to a smallscale, and one for low pressure, to a scale of twice thesize. The importance of an indicator may be estimatedfrom the enormous amount of fuel consumed in thiscountry for steam-power, a large quantity of whichwould be saved were the value of the indicator betterunderstood by the proprietors of steam-engines.]

2. Drawing of section of large indicator, showing theconstruction.

3. Indicator diagrams to an enlarged scale.

4. McNaught’s oil-testing machines. In spinning,weaving, &c., a large number of small spindles are kept inrapid motion, and if lubricated with an inferior oil, theirfriction, and, consequently, the non-productive load onthe engine, is materially increased. A small quantityof the oil to be tested is poured into the cup, a plate isthen placed on the top of the oil, and the cup set in rapidmotion. The plate is dragged round also, by the tenacityof the oil, and raises the weight on the steel-yard, byadjusting which, until an equilibrium is established, thefriction of the oil can be read off on the scale. Inventedky W. McNaught, C.E., of Glasgow.

5. Design for the application of McNanght’s patentexpansive principle to a 30 -horse engine. By this plan,high-pressure steam can be applied with safety to engineswhich have been designed originally for low-pressuresteam only. A small cylinder is applied at the crank endof the beam, at about half-stroke, and the steam from itpasses into the existing cylinder, where it expands, andwhence it finally escapes into the condenser, in the usualway. By this means a saving of from 30 to 40 per cent,of fuel is effected, and the power of the engine may beincreased, if desired, to the same extent.

102 Potts, J., Stockton-on-Tees— Manufacturer.Complete working model of the high-pressure steam-

engine, with several parts made of glass, as the cylinderand steam chest, showing the working of the piston andsteam slides, and the internal structure of the engine.

[This may be called the transparent high-pressuresteam-engine, the invisibility of the steam being a causeof wonder to many observers. Such a model is of thegreatest utility to lecturers and others engaged in teach-ing the principles of practical science.]

103 Hodges, B. J., Groce House Lodge, Outer Circle,

Regent’s Park —Inventor.

Working sectional model of a marine condensing steam-engine, for the use of schools and institutions.

104 Sharp, William Douglas, Swindon , Wilts —Inventor.

Steam-engine, with improved valves, valve-gear, &c.

The valves may be described as an elongation of thecylinder at each end in which the valves work; they areformed similar to, and of the same diameter as the piston,only that they are made hollow, with openings left inthem large enough for the exhaustion. The ports formnarrow openings extending quite round the circumferenceof the cylinder. The advantage of this description ofvalve is, that it gives a free inlet and outlet to the steam,which cannot be obtained with the slide-valve, especiallyat high velocities, as in the locomotive-engine, where theloss arising from this cause ranges from 30 to 50 percent. Another advantage which this valve also possessesis, that the pressure on the back of the valve, which is sodetrimental to the working of the slide-valve in loco-motives and other high-pressure engines, is avoided.

Although the eccentric is quite applicable for workingthis description of valve, a motion is substituted whichhas many advantages; which, with the reversing motion,will be understood from inspection. One valve-shaft issufficient for a pair of engines, care being taken to makethe angle between the point of contact of the cams withthe valve-rods the same as that formed by the cranks.

The mode of working expansively is only indicated bythe cross-rod and the double joint on valve-rod.

105 Bevan, Hopkin, Llanelly —Inventor.

Plan of a locomotive steam-carriage for common roads.

106 Beckett, E. G., 3 Joynson Street, Strangeways,

Manchester —Manufacturer.

High-pressure steam-engine, suitable where small poweris required.

108 Webster, Benjamin, 5 Stracey Street, Stepney,near Commercial Road Hast —Maker.

Working model of a pair of oscillating engines, of 300-horse power, on a scale of ^ inch to the foot, with eccen-tric paddle-wheels connected, showing the working of theengines, and the feathering of the floats.

112 Perry, Henry, Bromley, Bow —Manufacturer.

Model of a condensing engine and boiler, complete andconstructed to scale.

113 Shaw, B. L., Newhouse, Huddersfield —Inventor.

Model of Whitham’s patent hydraulic engine, designedas a substitute for the steam-engine in certain localities.This engine is said to have opened a great extent ofmining-ground in Swaledale, Stonesdale, and Coverdale,in Yorkshire , and in Weardale, in Durham.

116 Linton, John, Selby, Yorkshire — Inventor andManufacturer.

Model of an improved engine working high-pressuresteam expansively, with power to cut off the steam at anypart of the stroke, and finally condensing it, so as to effecta saving of fuel.