1833J 



physical cli.iris, and wLiL-h was lure nair.ed tl:e Jai'auess Current, 

 from its aiialoa'ous relation to Florida and the jitlantic Gulf 

 Stream. 'I his Gulf Stream of the Pacific was t'len traced by 

 direct observation and iiifeience, from numerous authorities who 

 were quoted, aei'oss the entire breadth of the Pacitie, to the N.W. 

 coast of America. Its eti'ect on the climaie of Sitka and Prince 

 AVilliam's Sound were shown to be similar to that on the coast of 

 Norway. The teai[jeratu:'e and the wiecks of Japanese junks, 

 the drift of timber to the Sandu'ich Islands, &e., proved the cir- 

 culation of the wateis around the lat. of 30 o , to be the same as 

 in the other thermal systems described. The ocean waters flow 

 southward, down the American coast toward the Bay of Panama 

 or the Great Bight, formed b}' the American Isthmus; and the 

 new and \eiy important cui-rent Avas then described, and the 

 numerous autlioritieson which it might be established were quoted. 

 It is a zone of easlcrhj drift, between lat. 50 ° and 60 ° N., 

 extending all across the Pacific, from the Pellew Islands, nearly 

 to the Bay of Panama, and was nanied the Equinoctial Counter 

 Current, Tliis singular current has an exact i-elationship to the 

 Guinea Current, on the 0|iposite side. The origin of this was 

 supposed to be due to the action of the N. N. E. and S. E. trade 

 wuids, forcing the waters up to thfse latitudes, cause them to 

 reverse their normal action ; and thus the waters appear all to 

 flow toward that one point, of such great intei'est at the present 

 time. The navigation about Panama was shown to be very crit- 

 ical and difiicult. Respecting the question of the level of the two 

 oceans, if it were not for the counter current it might be I'eason- 

 ably supposed that the Atlantic would be several feet higher than 

 the Pacific, from the waters in each ocean being drifted to their 

 western sides, but which are thus almost exactly balanced. After 

 some complimentary remarks fiom the President, the meeting- 

 was adjourned. 



ERICSSO^''S ENGINE. 



249' 



On Eri'ssoii's Hot Air, or Culoiic Eiisinr; by Wiliinm A. 

 Nortuii, I'lofiissDr ol Civ;! ti^iiginecii. g in Yale Coll;se.* 



The engines of the Caloric Ship Ericsson consist of four large 

 double cylinders, "standing in a fore-and-aft line; two before and 

 two abaft the shaft of the paddle wheels, and working in ]iairs 

 upon it." Each cylinder is double, the two cylinders being 

 placed one above the other. The lower one, which is the larger 

 of the two, is called the working cylinder, ami the other the sup- 

 ply cylinder. The working cylinder is entirely open at the top, 

 and the sujiply cylinder at the bottom. The pistons which play 

 in the two cylindei's are connected by eight strong iron colunms, 

 and move up and down together; the length of the stroke is 

 therefore, of necessit}', the same for each, viz: 6 feet. For the 

 sake of distinction, the piston in the woi'king cylinder is called 

 the woi'king piston, and the piston in the sup]ily cylinder the 

 supply piston. Underneath each working cylinder is a fm-nace, 

 which heats the air in this cylinder beneath the piston, and by 

 thus increasing its expansive force, furnishes the moti\c power of 

 the engine. The expansive foi-ce of this heated air drives the 

 working piston up, and with it the sujiply piston. Duiing the 

 ascent the air above the supply piston which is compressed befoi-e 

 it passes through a communicating pipe into the working cylin- 

 der, and receiving an accession of heat keeps up the ascensional 

 foi-ce. When the ]5istons have reached their highest point, a 

 valve is opened by the machine, which establishes a free commu- 

 nication between the compressed and heated air under the work- 

 ing piston and the external air ; it flows out, and the two con- 

 nected pistons descend by their own weight. It is to be observ- 

 ed, liowever, that the mechanical effect of this descending weight 

 is but a compensation for the diminution of mechanical effect 

 produced by the same weight in the ascent, and that the weight 

 of the pistons therefore forms, no part of the real moti\'e power of 

 the engine. 



Confining our attention to the pair of double cylinders posited 

 on either side of the main shaft, in the vacant space between the 

 working and supply cylinders is placed a horizontal working 

 beam, turning upon a shaft lying between the two double cylin- 

 ders. One of the supply pistons is connected with one end of 

 this working beam and the other with the other end ; by means 

 of links and connecting rods: and so, by the alternate action of 

 the two working pistons, a reciprocating movement is communi- 

 cated to the working beam. It will be seen therefore, that one 

 double cylinder^ with the necessary appurtenances, constitutes a 

 single acting engine, and that each contiguous pair of double 

 cylinders, standing on either side of the main shaft, by the con- 

 nection of their pistons with the opposite ends of a working 

 beam,ybr;?i. a double acting engine; that they accomplish the 

 same end as one double acting steam engine. 



The shaft of the paddle wheels of the Ericsson is, accordingly 

 driven by two double acting engines; one before and the other 

 abaft the shaft. Each of these engines has its sepai-ate workmg 

 beam. The power is transferred from each of these working 

 beams to the shaft, (which, it is to be observed, is considerably 

 elevated,) by means of a connecting rod passing from the nearer 

 end to the crank of the paddle-shaft. The two connecting rods 

 are attached to the same crank-pin ; and the relative position of 

 the shaft and working beams is such that each of the connecting 

 rods has a mean deviation of about 45 ° from the vertical posi- 

 tion, and when one rod is passing the dead centre the other is 

 acting upon the shaft with the maximum leverage. 



From what has been stated, it will be seen that in studying 

 the essential theory of the new engine, we may confine our at- 

 tention to one of the double cylinders with its accompan3'iug 

 mechanical arrangements, which taken together form one single 

 acting engine. The essential parts of this engine are shown in 

 the annexed diagram, which is a copj' of Ericsson's representa- 

 tion of the stationary engine. These are, respectively, the double 

 cylinder, with the pistons and piston rods ; the furnace, a large 

 vessel communicating by pipes with the top of the supply cylin- 

 der and the bottom of the working cylinder, called the JReceiver ; 

 and a piece of apparatus placed in the lowermost of these pipes, 

 called the Regenerator. The working piston in the engines of 

 the Ericsson, has a diameter of 14 feet, and the supply piston a 

 diameter of 1 1 feet 5 inches. The ratio of the areas of these 

 pistons, and therefore also the ratio of the volumes of the two 

 cjdinders is as 3 to 2. The working piston is six feet deep, and 

 concave underneath to fit the cylinder-bottom. The top and 

 bottom, as well as the sides, are of iron, but the space between 

 them is filled with gypsum and charcoal, non-conductoi's of heat. 

 The packing of the piston is at the top. The working cylinder 

 is of necessity prolonged six feet below the position of the top of 

 the piston when at its lowest point, thus forming a large vessel 

 called the heater, or heating chamber, into which the air passes 

 from the receiver. By this arrangement the packing at the top 

 of the piston never comes into contact with an}^ nortion of the 

 cylinder that is touched by the hot air. The grate of the furnace 

 is five feet below the ajiex of the dome-shaped cylinder-bottom. 

 Anthracite coal is used, and acts by radiant heat alone. The 

 supply cylinder is merely a great condensing air-pump, which 

 forces fresh air into the receiver, to be thence transmitted to the 

 heating chamber under the working piston. The supply piston 

 is furnished with thirty-six self-acting valves, which open upwards 

 and through which the air is admitted into the cylinder, in the 

 descending stroke of the piston. During the ascending stroke 

 these valves remain closed, and the compressed air opens another 

 set of valves at the top of the cylinder, and flows along the con- 

 necting pipe into the receiver. These two set of valves may be 

 called respectively, the outlet and the inlel vales. The valve ar- 

 rangement represented in the diagram is a little different; both 



