102 Steam Navigation.

steam-yacht, which was charged 215/.—A safety-valve would cost about 4/. and a mercurial* tubefor the same purpose 2l .—Had declined purchas-ing the Norwich steam-packet because it had ahigh-pressure engine.—Went with a party of Ger-man gentlemen from Bremen, who were anxiousto make an immediate purchase of a steam-vessel;and they also declined to purchase that, or any ofthe boats upon the river Yare, solely becausethey had high-pressure steam engines on board.

Mr. Richard Wright, of Blackfriars Road, En-gineer, called in and examined.

The boiler of the Norwich steam-vessel was eightfeet long, with a cylindrical boiler four feet twoinches diameter; it was first made with an in-ternal angle iron at one end, and an externalangle iron at the other end. In consequence ofthe internal angle iron having given way, a castiron end was substituted, which certainly was notaccurately performed. It was originally intendedto sustain a pressure of forty pounds to the inch.—Should think that both wrought and cast-ironboilers might be used with equal safety; but that,in proving them, they ought to be kept under thepressure a considerable time, say a quarter of anhour, or half an hour. Sudden pressure maycause flaws in a boiler, which may give rise toaccident afterwards; but, if under pressure aconsiderable time, the action of it might beseen.