September 25, 1914] 



SCIENCE 



433 



dam up some low ground or gorge between 

 two hills, above which the drainage of a 

 large area is collected. Such artificial 

 reservoirs are peculiar to the granitic coun- 

 try, and wherever groups of granite hills 

 occur taiiks are sure to be found associated 

 with them." Take again the great ship 

 canals. The Suez Canal runs for 100 miles 

 from sea to sea, though for part of its 

 course it runs through water, not through 

 sand. It is constantly growing in depth 

 and width. Its original depth was 26| feet ; 

 it is now, for nine tenths of its length, over 

 36 feet, and the canal is to be further deep- 

 ened generally to over 39 feet. Its original 

 width at the bottom was 72 feet ; it is now, 

 for most of its course, over 147 feet; in 

 other words, the width has been more than 

 doubled. A writer in the Times on the 

 wonderful Panama Canal said : ' ' The locks 

 and the Gatun dam have entailed a far 

 larger displacement of the earth's surface 

 than has ever been attempted by the hand 

 of man in so limited a space." Outside 

 the locks the depth is 45 feet, and the min- 

 imum bottom width 300 feet. The official 

 handbook of the Panama Canal says : " It is 

 a lake canal as well as a lock canal, its domi- 

 nating feature being Gatun Lake, a great 

 body of water covering about 164 square 

 miles." The canal is only fifty miles long 

 from open sea to open sea, from shore line 

 to shore line only forty. But in making it 

 man, the geographical agency, has blocked 

 the waters of a river, the Chagres, by build- 

 ing up a ridge which connects the two lines 

 of hills between which the river flows, this 

 ridge being a dam 1^ miles long, nearly 

 half a mile wide at its base, and rising to 

 105 feet above sea-level, with the result that 

 a lake has come into existence which is three 

 quarters of the size of the Lake of Geneva, 

 and extends beyond the limits of the Canal 

 zone. 



Mr. Marsh, in his book, referred to far 



more colossal schemes for turning land into 

 water, such as flooding the African Sahara 

 or cutting a canal from the Mediterranean 

 to the Jordan and this submerging the basin 

 of the Dead Sea, which is below the level of 

 the ocean. The effect of the latter scheme, 

 he estimated, would be to add from 2,000 to 

 3,000 square miles to the fluid surface of 

 Syria. All that can be said is that the wild- 

 cat schemes of one century often become 

 the domesticated possibilities of the next 

 and the accomplished facts of the third; 

 that the more discovery of new lands passes 

 out of sight the more men's energies and 

 imagination will be concentrated upon de- 

 veloping and altering what is in their 

 keeping; and that, judging from the past, 

 no unscientific man can safely set any 

 limit whatever to the future achievements 

 of science. 



But now, given that the proportion of 

 land to water and water to land has not 

 been, and assuming that it will not be, ap- 

 preciably altered, has water, for practical 

 purposes, encroached on land, or land on 

 water ? In many cases water transport has 

 encroached on land transport. The great 

 isthmus canals are an obvious instance; so 

 are the great Canadian canals. The ton- 

 nage passing through the locks of the Sault 

 St. Marie is greater than that which is car- 

 ried through the Suez Canal. Waterways 

 are made where there was dry land, and 

 more often existing inland waterways are 

 converted into sea-going ways. Manchester 

 has become a seaport through its ship 

 canal. The Clyde, in Mr. Vernon Har- 

 court's words, written in 1895, has been 

 "converted from an insignificant stream 

 into a deep navigable river capable of giv- 

 ing access to ocean-going vessels of large 

 draught up to Glasgow." In 1758 the 

 Clyde at low water at Glasgow was only 

 15 inches deep, and till 1818 no seagoing 

 vessels came up to Glasgow. In 1895 the 



