76 The National Geographic Magazine 



reported for any part of the bay. At 

 the head of the bay high tide is about 

 20 feet above mean sea-level. Low tide 

 is as much below. The tidal bore is 

 seen in Maccan River, entering Cum- 

 berland Basin ; but it is stronger in 

 Petitcodiac River, entering Shepody 

 Bay. It is best seen at Moncton, where 

 the first pair of views is taken. 



Mr Hayward gives the following de- 

 tails : 



The Petitcodiac River turns at Monc- 

 ton from a northeast to a southeast 

 course, then entering the northwestern 

 branch of the bay. The mud flats are 

 three-quarters of a mile wide at Monc- 

 ton. The retiring tide leaves them cov- 

 ered with ripple-marks. The low-tide 

 view was taken at 10.05 a. m., August 

 9, 1903, looking easterly. Here the 

 foaming and roaring bore advances 

 against a swift fresh- water stream, ris- 

 ing rapidly. Its height was about 3^2 

 feet ; its progress was 5 miles an hour. 

 High water, as shown in the second 

 view, is reached about three hours after 

 the arrival of the bore. 



The second pair of views was taken 

 at Wolfville, on the eastern arm of the 

 bay near the mouth of the Gaspareaux 

 River, on September 7 and 8, 1903. The 

 piles in the pier are stated to be 60 feet 



high. The great inconvenience attend- 

 ing so strong a range of tide may be 

 imagined. 



It may be well to recall a feature of 

 the Bay of Fundy tides set forth by 

 M. S. W. Jefferson a few years ago in 

 his articles in this magazine, to the 

 effect that the Fundy tides are practi- 

 cally synchronous fiom the mouth to 

 the head of the bay, while the Chesa- 

 peake tides, for example, are progress- 

 ively later and later from mouth to 

 head ; but the estuaries at the head of 

 the Bay of Fundy have progressive 

 tides, as in the Petitcodiac. The synch- 

 ronous ' ' swash ' ' tides of the bay may be 

 easily imitated in a model of an irregu- 

 lar shore on which a shallow sheet of 

 water lies. Tide-like oscillations in the 

 water may be made by an oscillating 

 plunger ; and when the proper period 

 of oscillation is chosen, the tide in a 

 funnel-shaped bay will have small range 

 at the mouth and great range at the 

 head, and the time of high or of low 

 tide will be essentially synchronous all 

 along the bay sides. At the same time 

 a neighboring bay of different form may 

 have progressive tides whose advancing 

 waves may assume the form of a bore 

 if the proper variation of breadth and 

 depth of channel is given. 



W. M. D. 



FRENCH CONQUEST OF THE SAHARA* 



By Charles Rabot 



Editorial Secretary of "La Geographie," Member of the Council 

 of Societe de Geographie de Paris 



TO traverse the Sahara from north 

 to south, to join Algeria to the 

 Sudan through the great des- 

 ert of North Africa, and to subjugate 

 the nomads who wander through that 

 immense region has been one of the 

 principal aims of France in recent years, 



and one which she has at length attained 

 at the price of long and persevering ef- 

 fort. The hostility of the Touaregs was 

 for a long time an obstacle. Established 

 in the oases scattered over the Sahara, 

 these Berber fanatics and brigands were 

 accustomed to scan the whole desert, and 



* An address to the Eighth International Geographic Congress, September, 1904. 



