76 



Notice and description of a Marine Ventilator. 



same, as to permit it to turn without suffering the air to escape from 

 one to the other division ; preserving as little communication of air 

 between the compartments as possible, This midriff is to be opera- 

 ted by pistons, or pitmans, attached to it in each of the upper com- 

 partments, and passing through the top of the box, they are connected 

 with a break, or lever, resting in a fulcrum in the centre of tlie top of 

 the box, and for the convenience pf working it, extending at each 

 end beyond the end of the box. 



Through the perpendicular sides of the box, and as near the axis 

 of the midriff as may be, without interfering wdth its motion, are 

 four apertures on each side, to admit and discharge the air. These 

 apertures are governed by valves j one on each side of each of the 

 upper and lower compartments, opening inward ; and one in each, 

 opening outw-ard j and that transversely. Over each two of the 

 valves, in the upper and lower compartments, respectively. Is placed 

 an air-tight cell, calculated to receive a general conductor of air, to 

 or from the valves it covers. Thus on the vibration of the midriff, 

 at the descending end, the fresh air is drawn into the upper compart- 

 ment through the inside valve, while the foul air is driven out of the 

 lower compartment at the same end, through the outside valve ; and 

 vice versa. 



. From the cells which cover the valves, conductors extend respec- 

 tively to the hold of the vessel, at different and remote part_s of it, 

 one to inhale at one part, the foul air, and another, at another part, 

 to exhale the fresh air ; w^hile others extend abroad in different di- 

 rections, one to inhale at one place the fresh air, and another at a re- 

 mote part of the vessel, to exhale the foul air. Thus a continual 

 current of fresh and foul air, respectively, is passing through the ven- 

 tilator : the fresh air through the upper compartments, and the foul, 

 in an opposite direction, through the lower ; so that a fourfold opera- 

 tion is performed by every stroke or movement of the lever which, 

 governs the midriff; to wit, inhaling fresh air at one valve, exhaling 

 fresh air at another; inhaling foul air at one, and exhaling foul at an- 

 other ; and this alternately. 



This machine is to be suspended under the deck of the vessel, 

 through which the pistons, or pitmiins, by which it is worked, pass ; 

 and in the most convenient part : Or it may be in a detached and 

 moveable form, and worked altogetlier above dccks^ or in the vessel's, 

 hold. The pipes, or conduits, to convey the air, may be eitlicr stout 

 leathern hose, or w^ooden, or metallic tubes, passing to the different 

 arts of the hold, under the deck* 



