§ 378. CURRENTS OF THE SEA. I79 



going on. Hence we infer that there is from the Eed Sea an un- 

 der and outer current, as there is from the Mediterranean through 

 the Straits of Gibraltar, and that the surface waters near Suez are 

 Salter than those near the mouth of the Eed Sea. And, to show 

 why there should be an outer and under current from each of 

 these two seas, let us suppose the case of a vat of oil and a vat of 

 wine connected by means of a narrow trough — the trough being 

 taken to represent the straits connecting seas the waters of which 

 differ as to specific gravity. Suppose the trough to have a flood- 

 gate, which is closed until we are ready for the experiment. Now 

 let the two vats be filled, one with wine the other with oil, up to 

 the same level. The oil is introduced to represent the lighter wa- 

 ter as it enters either of these seas from the ocean, and the wine 

 the same water after it has lost some of its freshness by evapora- 

 tion, and therefore has become Salter and heavier. Now suppose 

 the flood-gate to be raised, what would take place? Why, the oil 

 would run in as an upper current, overflowing the wine, and the 

 wine would run out as an under current. 



878. The rivers which discharge their waters into the Mediter- 

 The Mediterranean raucau are not Sufficient to supply the waste of 

 current. cvaporatiou, and it is by a process similar to this 



that the salt which is carried in from the ocean is returned to the 

 ocean again ; were it not so, the bed of that sea would be a mass 

 of solid salt. The equilibrium of the seas is a physical necessity. 

 Were it to be lost, the consequences would be as disastrous as 

 would be any other derangement in the forces of attraction. With- 

 out doubt, the equilibrium of the sea is preserved by a system of 

 compensation as exquisitely adjusted as are those by which the 

 "music of the spheres" is maintained. It is difficult to form an 

 adequate conception of the immense quantities of solid matter 

 which the current from the Atlantic, holding in solution, carries 

 into the Mediterranean. In his abstract log fpr March 8th, 1855, 

 Lieutenant William Grenville Temple, of the United States ship 

 Levant, homeward bound, has described the indraught there : 

 " Weather fine ; made IJ pt. lee-way. At noon, stood in to Al- 

 miria Bay, and anchored off the village of Eoguetas. Found a 

 great number of vessels waiting for a chance to get to the west- 

 ward, and learned from them that at least a thousand sail are 

 weather-bound between this and Gibraltar. Some of them have 

 been so for six weeks, and have even got ns f]r p.s IVfnlnga, only 



