WRV DO SPEIJYGS AND WULLS OVERFLOW ? 407 



instead of a diiference of three hundred and sixty-five feet " ! Here 

 is where Mr. Green should have brought in his ideas on friction, and 

 have studied Professor Buckland's address more closely. In that 

 address it is stated that "the surface-line of any subterranean sheet 

 of water may be ascertained by measuring a series of wells at distant 

 intervals along the dip of the stratum under examination. . . . Mr. 

 Clutterbuck had further observed that the surface-line of subterranean 

 sheets of water was not horizontal, like the surface of a lake, but 

 inclined at a rate varying from fourteen to twenty feet per mile, in 

 consequence of friction caused by the particles of the strata through 

 which those sheets of rain-water descended with retarded motion to 

 be discharged by springs. This inclination of the subterranean water- 

 line in the chalk of Hertfordshire had been found, by Mr. Clutterbuck, 

 to be nearly at the rate of twenty feet per mile in the chalk between 

 Sir John Sebright's park at Beechwood and the town of Watford ; and 

 fourteen feet per mile in the chalk under tertiary strata in some parts 

 of the basin of London. The engineers of the Southampton Railway 

 had found a similar fall of about sixteen or seventeen feet per mile in 

 the wells at the railway-stations between Basingstoke and South- 

 ampton." Without expressing an opinion of my own as to whether 

 there really is or is not a subterranean water-channel between Lakes 

 Superior and Ontario, it is evident enough that, even if there is, its 

 size and character, as being more or less obstructed by solid or porous 

 materials, together with its length, would have sojne influence in de- 

 termining the quantity of water which could flow through it, even 

 with a difl^erence of water-level over its extremities equal to three 

 hundred and sixty-five feet. Unless, therefore, Mr, Green's " newly 

 discovered force" should suddenly cease to make Lake Superior an 

 "overflowing spring of subterranean water," or, rather, unless the 

 region from which Lake Superior gets its water should be deprived of 

 its yearly rains, we need not immediately look for a common level of 

 the water in Lakes Superior and Ontario. 



