176 PHYSICAL GEOGKAPHY OF THE SEA, AND ITS METEOROLOGY. 



fore heavier water, must either rim out as an under ciuTent, or it 

 must deposit its sm-phis salt in the shape of crystals, and thus 

 gradually make the bottom of the Ked Sea a salt-bed, or it must 

 abstract all the salt from the ocean to make the Ked Sea brine^ 

 and we know that neither the one process nor the other is going 

 on. Hence we infer that there is from the Eed Sea an under and 

 outer cm-rent, as there is from the Mediterranean through the 

 Straits of Gibraltar, and that the sm^face 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 fr'om each of these two 

 seas, let us suppose the case of a vat of oil, and a vat of wine con- 

 nected by means of a narrow trough — the trough ])eing 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 water as it 

 enters either of these seas from the ocean, and the wine the same 

 water after it has lost some of its fr'eshness by evaporation, 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 

 rmi out as an under cmTent. 



378. The rivers which discharge thefr v\'aters into the Mediter- 

 The Mejiterranean raucau are uot 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 retiu'ned to the 

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

 solid salt. The mistable equihbrium of the seas is a physical 

 necessity. Were it to be lost, the consequences would be as dis- 

 astrous as would be any derangement in the forces of gravitation. 

 Without doubt, the equihbrium of the sea is preserved by a system 

 of compensation as exquisitely adjusted as are those by w^hich the 

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

 adequate conception of the immense quantities of sohd matter which 

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

 Mediterranean. In his abstract log for March 8th, 1855, Lieu- 

 tenant Wilham Grenville Temple, of the United states ship Levant, 

 homeward bound, has described the indraught there : " Weather 

 fine ; made 1 J pt. lee-way. At noon, stood in to Almiria Bay, 

 and anchored off" the village of Eogiietas. Found a great number 

 of vessels waiting for a chance to get to the westward, and learned 



