no chiinnels of circulation by wliicli tlicy could pass out into the ocean, and traverse different latitudes and 

 clim^iles, then the waters ofthese arms and seas would, as to their constituents, become in the process of time very 

 different from the sea waters in other parts of the world. 



For instance, take the Red sea and the Mediterranean by way of illustration : upon the Red sea there is 

 no precipitation. It is in a rainless region ; not a river runs down to it; not a brook emj)ties into it; therefore 

 there is no process by which the salts and Wrtshings of the earth which are taken up and hi Id in solution by rain oi 

 river water, can be brought down into the Red sea. The air takes up from it in the process of evaporation 

 fresh water, leavinar behind all the solid matter which the sea there holds in solution. 



On the other hand, numerous rivers discharge into the Mediterranean ; some oi which are fdtered 

 through soils and among minerals which yield one kind of salts or soluble matter; another river runs 

 through a limestone or volcanic region of country, and brings down in solution solid matter, it may be common 

 salt, sulphate or carbonate of lime, magnesia, soda, potash or iron ; either or all may be in its waters. Still the 

 constituents of sea water from the Mediterranean, and of sea water from the Red sea, are quite the same. But 

 the waters of the Dead sea have no connection with those of the ocean : they are cut off from its channels oi 

 circulation and are therefore quite different as to their components from any arm, frith or gulf of the broad 

 ocean.* 



How therefore shall we account for this sameness of compound, but upon the supposition of a general 

 system of circulation in the ocean, by which in the process of time, water from one part, is conveyed to another 

 part the most remote, and by which a general interchange and commingling of the waters take place ? 



In like manner, the constituents of the atmosphere whether it be analysed at the equator or the poles, 

 are the same. By cutting off and shutting up from the general channels of circulation any portion of sea 

 water, as in the Dead sea, or of atmospheric air, as in mines or wells, we can easily fill cither with gasses or 

 otlier matter that shall very much effect its character and alter the proportions of its constituents 



The principle agents that are supposed to be concerned in giving circulation to the atmosphere, and in 

 preserving the ratio among its components, are light, heat, electricity and perhaps magnetism : but as far as 

 the motive power is concerned, or that agency by which the atmosphere that may now be within the tropics is 

 wafied to the poles, heat and electricity are supposed to be the chief among them. 



But with regard to the sea, it is not known what office is performed by electricity and magnetism in driving 

 dynamical force to the system of oceanic circulation. The chief motive power from which marine currents 



• " The solid constituents ot"sea water amount to about 3| per cent, of its weight, or nearly half and ounce to the pound, lis salt- 

 icss may be considered as a necessary result of the present order of things. Rivers which are consuintly flowing into the ocean contain 

 ■iuliM varying in amount from 10 to 50 and even 100 grains per gallon. They are chiefly common salt, sulphate and carbonate of lime 

 magnesia, soda, potash and iron ; and these are found to be the main constituents of sea water. The water which evaporates from the' 

 .sea is nearly pure, containing but very minute Iraces of salts. Falling as rain upon the land, it washes the soil, percolates throuo-h the 

 rocky layers, and bec.funes charged with saline substances which are borne seaward by the returning currents. The ocean, therefore is 

 the great depository of every thing that water can dissolve and carry down from the surface of the continents ; and as there is no channel 

 fin- lluir escape, they of course constantly accumulate."— ( Fokhwiis' Chemistry.) 



•'The case uf the sea, "says Fowner, "is but a magnified represenUition of what occurs in every lake into which rivers flow, but 

 in.n. win vh there is ,,o outlet except by evaporaiion. Such a lake is invariably a salt lake. It is impossible thai it can be otherwise ■. 

 and II is curious to observe that this condition disajipears when an uriificial outlet is pn.duced for the waters." 



