This improvement is designed to render nearly the whole capacity of the air pump of a marine engine available as a water pump to free the hold of a ship in case of. accident, or from the ordinary accumulation of bilge water, without in any way interfering with its efficiency as an air pump, or impairing the vacuum in the condenser. Our engraving represents a vertical section of oae of the air pumps, condensers and hot wells of the steamship Arctic, lost some years siuce between Liverpool and New York. The condenser is represented provided with the ordinary injection pipe, B, to which a bilge injection may be attached if desired. A channel way, C, provided with foot valves, D D, leads from the condenser to the air-pump, E, in which moves a piston, F, having in it n proper bucket valve and seat, G G. This pump is in connection with a hot well, H proper delivery doors, J J, being applied between the twowhich hot well communicates with the outside of the ship, through a pipe, K, commonly known as a discharge or waste pipe, through which the air, water, and vapor delivered by the air pump pass overboard. What constitutes this improvement is the attachment to the body of the pump, ncar the top thereof, of an indepeudent suction pipe, L, which pipe, L, extends down into the hold of the ship, and is provided with a screw, stop valve, 0, and two ordinary ball valves, P Q, one of which latter may be dispensed with if desired. When the stop valve, 0, is closed, the air pnmp, E, operates precisely the same as beforo the pipe, L, is attached. When, however, the valve is opened, there being water in the hold of. the vessel, and after the piston, in its upward stroke, has delivered the water from the condenser, and commenced its descent, leaving a vacuum above the bucket, water will, by the pressure of the atmosphere, rise through the pipe, L, lifting the ball valves, P and Q, in its passage, and fill the pump as the piston descends, uutil the air, vapor and water below the piston, drawn from the condenser on its previous up stroke, by their superior pressure, open the bucket valve of the piston. The said bucket valve then passes into the channel way, C, and again takes hold of the condensing water, in the same manner that it did on its previous stroke, and as it re-ascends will again exhaust the condenser of water, air and vapor, and at the same time deliver the whole contents of the air pump, comprising the water drawn from the condemer, and that drawn from the hold of the vessel, through the pipe, L, into the hot well, H, ana from thence through the discharge pipe, K, overboard, and thus if will continue to act as long as there is water in the hold. Another advantage results from the use of this invention in the fact that all the chips, coal, &c., that may be drawn from the hold, instead of being drawn into the condenser and through the channel way, C, and foot and bucket valves, D G, tending to choke them up, as is the clise in the employment of the ordinary bilge injection, is drawn directly into the pump, above the bucket and foot valves, and thence through the hot well and pipe, K, overboard. It, moreover, gives a pumping capacity far exceeding auy pumping apparatus heretofore known, and being a necessary part of the main engine, it is not liable to rail, and is ready for all emergencies. It does not require increased machinery except the simple attachment of the suction pipe, L, and valves, 0 P Q, but simply renders the mnchinery already working on board steam vessels at all times available, without additional power to the pumping capacity demanded for public safety, and it is applicable to all marine condensing engines now in use. f\ To illustrate the benefits of this invention as '*) a means of security to life and property,. the JX. inventor mentions that had the ill-fated Jtpj steamer A,'ctic been provided with this simple attachment, her hold would have been kept sufficiently free from water to have enabled her to have been properly sustained and brought safely into port. To substantiate this opinion he gives certain facts in relation to this vessel as follows :The two air pumps of the AI'ctic were each five feet diameter and five feet stroke, making 196 cubic feet per revolution of the engine. The average number of these revolutions per minute was twelve, showing an aggregate of 2,352 cnbic feet, equal to 67 tuns of water per minute or 4,020 tuns per hour, which the air pujnps on board the Arctic were capable of discharging had they been provided with this simple attachment. Her whole tunnage was less than 3000 tuns, so that the capacity of the air pumps to discharge water from the hold per hour, at their average speed, exceeded the actual tunnage by more than one quarter, and therefore it is clear that with this improvement, it would have been impossible for her to sink under aleak less than wodd sink her under ordinary circumstances in one hour. It fol- lows, then, that as the Arctic was over five hours in filling and sinking, had this improvement been attached to the air pumps, the noble vessel with all lier 'treasure in life and property would in all likelihood have been safely brought into port. This invention was patented May 4, 1858, and any further information may be obtained from the inventor, Daniel Barnum, No. 2 Snssex place, Jersey City, N. J.