12 ANNUAL OF SCIENTIFIC DISCOVERY. 



outside of the boiler, below the water line. In this is a cylindrical 

 hollow float, having a vertical piston-rod at the top and bottom, to 

 each of which is attached a plug or piston, fitting into corresponding 

 circular apertures in the top and bottom of the brine-cylinder, con- 

 nected with the blow-off pipe. When the water in the brine-receiver 

 is below the limited standard of density, the float sinks to the bottom, 

 closing the lower orifice, but, as the density rises, the float is raised, 

 and a portion escapes. There is on the top of the receiver a glass 

 index-tube, in which a wire attached to the float-rod rises and falls, 

 indicating to the attendant what is going on within the boiler. Lon- 

 don Mining Journal, Sept. 28. 



SEA-STEAMERS BUILT IN THE UNITED STATES IN 1850. 



AFTER various unsuccessful attempts at building rapid sea-going 

 steamers, there have at last been completed some American steam- 

 ships, which, in point of speed and regularity, must take the highest 

 rank. During the past year four of the vessels of the New York 

 and Liverpool line of steamships, owned by E. K. Collins and others, 

 have commenced their voyages. They are called the Atlantic, Pacific, 

 Arctic, and Baltic. As they are much alike, a notice of the dimen- 

 sions of the Atlantic will suffice for all. She is 290 feet long on 

 deck ; 46 2 feet beam ; 32 feet depth of hold ; 3,300 tons carpenter's, 

 and 2,900 tons custom-house measurement. The interior decorations 

 are of the most costly character. The cost of each vessel was about 

 $ 600,000. The speed of these vessels is evidently very great, the 

 average of their passages being considerably less than that of the new 

 Cunard steamers, which are a great improvement upon the old vessels 

 of the same line. One improvement has been introduced into the Col- 

 lins steamers, which is calculated to add much to the comfort of pas- 

 sengers. It consists in warming every part of the ship by means 

 of steam-pipes supplied directly from the boilers. 



The Journal of the Franklin Institute for October gives a list of all 

 the sea-steamers built or building in the United States during the year 

 1850. The total tonnage is 42,097 tons. The four Collins (Liver- 

 pool) steamers make 12,000 tons; two Havre steamers, 4,100 tons; 

 twelve for the Pacific, 13,232 tons; eleven, intended to run coastwise 

 in the Atlantic and Gulf of Mexico, 9,765 ; two to Liverpool, 3,000. 

 The total number of vessels is thirty-one ; of which seven, with a ton- 

 nage of 5,925 tons, are propellers. 



NEW MODE OF APPLYING STEAM TO THE PROPULSION OF VESSELS. 



MESSRS. RUTHVEN, the \vell-known engineers of Edinburgh, have 

 invented a new mode of applying steam to the propulsion of vessels. 

 The arrangement consists in the forcible expulsion of water from a 

 nozzle, or bent pipe, at each side of the vessel, which is effected by 

 the power of the steam-engine. The form and properties of a sailing 

 vessel are preserved, there being no projections on the hull in the 

 form of paddle-boxes or otherwise. Under the engine, which is 



