The Mediterranean Sea 



annual temperature of the deepest water of the western basin. 

 During the forty years which have elapsed since Aime made 

 his experiments and speculations, further observations have 

 only tended to confirm his theory. It is true that the tem- 

 peratures observed in the many soundings which have been 

 made of late years have not shown absolute identity of tem- 

 perature, and it is probable that the greater the refinement in 

 the instruments used the more decided will the local differences 

 appear. Especially it will be apparent that the bottom tem- 

 perature varies with the climate of the preceding winter, and 

 the distribution of temperature varies much with the prevalence 

 of the winds. At the few stations where the temperature of 

 the sea-water and that of the air are regularly examined, it 

 appears that the water is generally for the greater part of the 

 year warmer than the air, and in winter considerably so. The 

 existing observations, however, are too few to justify any very 

 definite statement on the subject. At Palermo the sea is 

 warmer than the air throughout the whole year with the 

 exception of the months May and June. In Algiers Aime 

 found but little difference; in autumn and winter the water 

 was slightly warmer, in spring and summer slightly colder, 

 than the air. In the eastern basin we have first Admiral Spratt's 

 observations in July 1845 in ^Egina Gulf. In all his experi- 

 ments made previous to the year 1860 he determined the 

 temperature of the bottom water by taking that of the mud 

 brought up in the dredge. This is a very excellent method ; 

 in fact, it is probably the best of all methods if a sufficient 

 quantity of mud be obtained. From 1860 he used self- 

 registering unprotected thermometers, which gave results 

 necessarily too high, and it is impossible to apply any reliable 

 correction to them without experimentally determining it on 

 each thermometer which was used. By the first method 

 Admiral Spratt found 55-5 F. at depths between 100 and 

 200 fathoms. 



From these observations it seemed reasonable to conclude, 

 as Aime had done, that all over the Mediterranean a practically 

 uniform temperature is found at all depths greater than 100 or 

 200 fathoms, and that this temperature is 54 to 56 F. In 



