118 ‘“H. W. Pearson—Changes in the Sea- Level. 
The Encye. Brit., vol. xxii, p. 708, says: ‘Lines of level carried 
across the continent of Europe make the mean sea-level of the 
Mediterranean, at Marseilles and Trieste, from 2 to 5 feet below that 
of the North Sea and the Atlantic, at Amsterdam and Brest, a result 
which is not easy to explain on mechanical principles”? (my italics). 
In Sctence, vol. ii, the results from numerous lines of level in 
Europe are mentioned as follows:—Bourdalone in 1864 stated the 
average level of the Mediterranean to be 0°72 metre below that of the 
Atlantic. General Ibanez has shown the difference of level between 
‘Santander and Alicante as 0-66 metre, and between Marseilles and 
Amsterdam (through Alsace and Switzerland) as 0°80 metre. 
Other differences are shown between the Mediterranean and North 
Sea as follows:—Through Prussian levels, 0°757 metre, vid Alsace 
0°809 metre, through Switzerland 0:°832 metre, between Trieste 
and Amsterdam (vid Silesia and Bavaria) 0°59 metre. (Sevence, 
‘vol. ii, p. 54.) 
In Science, vol. vii, p. 75, we are told by Ferrel that the mean 
level of the harbour of Brest is 1:02 metre higher than the surface- 
level of Marseilles. 
In the United States we find the same condition. Some twelve or 
fifteen lines of levels from various points on the Atlantic coast result 
invariably in determining the Gulf of Mexico to be elevated above the 
waters of the Greater Ocean. 
Hilgard in 1884, from three sets of levellings, showed the Gulf at 
New Orleans as one metre higher than the Atlantic at Sandy Hook. 
(Sczence, vol. 11, p. 504.) 
C. A. Schott shows that the difference of level between Sandy Hook 
-and Lake Ponchartrain is 1-002 metre. (Scvence, vol. vii, p. 102.) 
Mr. John F. Hayford, in Appendix No. 8 (U.S. Coast and Geol. 
Survey Reps., 1899, pp. 897-431), has shown that the average of six 
-lines of precise levels run across Florida, from St. Augustine to Cedar 
Keys (1892, 1893, and 1894), gave as result the Gulf to be 2585 metre 
above the Atlantic. He also shows that a line from Old Point Comfort 
on the Chesapeake to Biloxi, Miss., found the excess in surface-elevation 
of the Gulf to be 1-028 metre, and a series of levels from Sandy Hook 
to Biloxi—evidently not the same lines as those mentioned by Hilgard 
and Schott—resulted in a difference of -385 metre. He furthermore 
gives an excess in the Gulf level of :175 metre, arrived at by way of 
a line from Boston and New York to Lake Ontario, thence to Chicago 
and Duluth, and thence by a most circuitous course to the Gulf. The 
extraordinary length of this line, however, would seem to render its 
conclusions less trustworthy than the more direct lines previously 
mentioned. 
In 1883 to 1886 the Canadian Department of Public Works caused 
a line of levels to be run from Quebec to Rouse’s Point, N.Y., where 
a bench-mark of known altitude above mean sea-level at Sandy Hook 
had been established by the U.S. Engineers. The result of this line was 
apparently to establish the fact that the sea-level at Quebec was some 
54 feet below that of New York (5:52 feet). This determination was 
unexpected to this writer, as from the application of Ferrel’s formula 
it would appear that the elevating effect of the southward-flowing 
