H, W. Pearson—Changes in the Sea-Level. TTS 
Labrador current, in immediate contact with the shore-line, would be 
much in excess of the depressing effect of the distant Gulf Stream. 
It seemed, therefore, impossible to explain mathematically this 
surprising lack of elevation in the St. Lawrence. 
Such explanation, however, no longer seems necessary. In the 
Trans. of the Can. Society of Civil Engineers for 1908, it has been 
shown by W. B. Dawson that the Admiralty datum at Quebec is 
8°58 feet below mean sea-level, and that by reason of this the mean 
sea-level at Quebec had been assumed as about 8 feet too low. 
Mr. Sproule then pointed out—‘‘ This would imply that the observed 
sea-level in Quebec was 383 feet higher than the sea-level at New 
York” (p. 124). Ferrel’s deductions are thus again confirmed. 
A rising gradient of exceptional magnitude is found in the line of 
levels run by Mr. Bunt in 1837 and 1838 from Portishead on the 
Bristol Channel, southward to Axmouth on the English Channel. 
This levelling was made at the instance of the British Association, 
and was one of the first attempts to introduce extreme accuracy into 
such labours. The result of nearly 9 inches excess in northern 
elevation, however, can hardly be ascribed entirely to the cause herein 
urged. Sir Charles Lyell (Principles, 9th ed., p. 295) has shown that 
‘<The rise of a tidal wave above the mean level of a particular sea 
must be greater than the fall below it.” Owing to the extreme range 
of tides in the Bristol Channel, it seems very probable that the greater 
portion of the observed elevation of 9 inches may be due to the 
operation of this last-named law. 
It would now seem that the illustrations above given are ample to 
establish the fact that Ferrel’s law is supported hy all actual 
differences in level of which we have knowledge. 
Heretofore, these differing elevations have been held as doubtful, 
absurd, and unexplainable. They have been regarded as in opposition 
to mechanical principle. The officers of our own Coast Survey. have 
rejected them utterly. They have held the Gulf and Atlantic to be at 
the same elevation, and have assumed the apparent elevation of the 
Gulf as due to some mysterious and systematic series of errors in 
levelling, by which, under some process still more mysterious, these 
distortions of fact have been made to appear always in one direction. 
Giving expression to their beliefs, they have also arbitrarily 
‘- adjusted”’ the elevations of some 4,000 bench-marks of the precise 
level lines of the United States, in an effort to eliminate these 
unexplainable differences. (See Report Coast and Geod. Survey, 
1899, App. 8.) 
The logic, the unquestioned value, the simplicity of Ferrel’s law, 
however, now bring fact and theory once again into harmony, In the 
ocean currents, crowding against, or flowing from, the oceanic coast- 
lines, we find perfect explanation of all known cases of discrepancy in 
altitude. 
We are now in position to advance one step farther in our 
examination as to the truth of Playfair’s law, and may reason 
somewhat as follows :— 
It will be admitted, I think without question, that the argument 
above presented has considerable weight, that there is mathematical 
