Curiosities of Science. 175 



times as great as the height of the highest mountain. Recent 

 soundings show depths in the sea much greater than any ele- 

 vations on the surface of the earth ; for a line has been veered 

 to the extent of seven miles. Dr. 



GKEATEST ASCERTAINED DEPTH OF THE SEA. 



In the dynamical theory of the tides, the ratio of the effects 

 of the sun and moon depends, not only on the masses, dis- 

 tances, and periodic times of the two luminaries, but also on 

 the Depth of the Sea ; and this, accordingly, may be computed 

 when the other quantities are known. In this manner Pro- 

 fessor Haughton has deduced, from the solar and lunar co- 

 efficients of the diurnal tide, a mean depth of 5'12 miles; a 

 result which accords in a remarkable manner with that inferred 

 from the ratio of the semi-diurnal co-efficients as obtained by 

 Laplace from the Brest observations. Professor Hennessey 

 states, that from what is now known regarding the depth of the 

 ocean, the continents would appear as plateaus elevated above 

 the oceanic depressions to an amount which, although small 

 compared to the earth's radius, would be considerable when 

 compared to its outswelling at the equator and its flattening 

 towards the poles; and the surface thus presented would be 

 the true surface of the earth. 



The greatest depths at which the bottom of the sea has been 

 reached with the plummet are in the North- Atlantic Ocean ; 

 and the places where it has been fathomed (by the United- 

 States deep-sea sounding apparatus) do not show it to be 

 deeper than 25,000 feet = 4 miles, 1293 yards, 1 foot. The 

 deepest place in this ocean is probably between the parallels 

 of 35 and 40 north latitude, and immediately to the south- 

 ward of the Grand Banks of Newfoundland. 



It appeal's that, with one exception, the bottom of the North- At- 

 lantic Ocean, as far as examined, from the depth of about sixty fathoms 

 to that of more than two miles (2000 fathoms), is literally nothing but 

 a mass of microscopic shells. Not one of the animalcules from these 

 shells has been found living in the surface-waters, nor in shallow water 

 along the shore. Hence arises the question, Do they live on the bottom, 

 at the immense depths where the shells are found ; or are they borne by 

 submarine currents from their real habitat ? 



RELATIVE LEVELS OF THE RED SEA AND MEDITERRANEAN. 



The French engineers, at the beginning of the present cen- 

 tury, came to the conclusion that the Red Sea was about thirty 

 feet above the Mediterranean : but the observations of Mr. 

 Robert Stephenson, the English engineer, at Suez ; of M. Ne- 

 gretti, the Austrian, at Tineh, near the ancient Pelusium ; and 

 the levellings of Messrs. Talabat, Bourdaloue, and their assist- 



