MARINE ENGINES.

491

socket; prior to which a blind flange with a short pipe accuratelybored and turned is slipped over the end of the shaft, with aring of india rubber placed over the short tube. The slings arethen put on the shaft, and when the top one can be attached to acrane, it is easily drawn out of the ball, the blind flange and shortpipe follows it up, and takes the place of the shaft, keeping thepacking in its proper position; the flange is then screwed up withthe same nuts as for the gland, and in this way a double protectionis afforded by the ring joint against water getting into the ship.The guiding shackle is then fastened to the manhole, and as it isonly a foot or so below the water, it acts as a guide in placing theshaft in again. When the shaft is clear of the ball it can be easilylifted out; and it is replaced in the same way; the ball being heldat the inclination by the nuts on the sector placed underneath thesocket. When the shaft is put in again, it is passed through thetop bearing brass, then through the guiding shackle, and is loweredinto the wooden bearing in the ball, and then into the short pipeon the blind flange. A small testing tap is fitted on the flange, forallowing the compressed water to escape, as also to prove if thepacking around the shaft is perfectly tight before withdrawing ortaking off the flange or pipe piece.

THE COMPOUND ENGINE.

The Cornish engineers have for a long period taken the lead inthe important matter of the economy of the steam engine, some oftheir large pumping engines doing duty with barely 3 lbs. of coalper actual horse power per hour. This result is due to the highsteam pressure used, cutting off the steam soon, and working witha large measure of expansion, for which the long stroke of thepiston in these engines is admirably suited; these facts, combinedwith the careful clothing of the parts where radiation takes place,account for the small amount of fuel consumed over that of ordinaryengines. The principle of compounding was tried many years agoby Hornblower, Woolfe, and M'Naught, but was not introducedsuccessfully into marine practice tili 1854, when Messrs. Randolph,Eider, & Co. fitted up the steamer Brandon. The first vessel of