ENGINE-ROOM FITTINGS.

ENGINE-R005

I FITTINGS. 337

land has been introduced by Mr. Porter, anAmerican gentleman, being the invention ofMr. Richards, also from the same country. Itis constructed by Messrs. Elliott Brothers,London, to whom the author is indebted forthe working drawings depicted by Fig. 215.This is a sectional and complete elevation of anindicator, embracing the latest improvementsin the connections, no screwdriver being re-quisite to disconnect any portion. The sectiondepicts the steam piston, spring and casing, alsothe motion barrel and the spring to cause thereaction. The complete view shows the leversconnected to the end of the piston rod, andthe portion containing the marker, which ismetallic, paper being used of a suitable nature.

It will be noticed that the levers form aparallel motion, thus causing a straight linefor the path of the marker. The stroke of thepiston is one-fourth of that of the marker,an advantage of the highest importance withhigh speeds, for which the instrument is welladapted.

The vacuum and steam gauges in the engineroom are located respectively on the exhaustand supply steam pipes in a prominent positionin the engine room. The gauge mostly adoptedis by Mr. Bourdon, being a coil of tubing filledwith mercury ; the pressure acting on the coilcauses the hand on the dial to indicate thepower exerted. Steam gauges are also fitteddirectly to the boilers.

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