Oil Artesian or Overflowing Wells. 11'7 



has already made us acquainted with one of the oldest spring- 

 wells of this kind*; and from Shaw, we learn, that^ even at 

 Algiers, in the village Wad-Reag, appearances exactly similar 

 to those in the Comte d'Artois are to be seen f . 



The number of these examples might certainly be increased ; 

 only the few which are already adduced, and the frequency of 

 the geognostic relations, which we have seen to be conditions to 

 the boring of Artesian wells, will sufficiently justify the conclu- 

 sion, that wherever these relations occur, we may calculate on 

 meeting with a spring of water. By no means, however, ought 

 the vain hope to be indulged, which has been pubhshed within 

 this short time in a very uncritical essay in the Bibliotheque 

 Universelle, t. xxxix. p. 193 and 204-, that, in every part of the 

 earth where we bore skilfully, a fortunate result may be ex- 

 pected. 



Even in a district of the proper constitution, the meeting with 

 these springs depends, in some measure, on accident. Where, 

 for example, we must sink into the limestone itself, the result 

 is naturally dependent on our meeting in time with a vein of 

 water or not. Thus Gamier mentions, that an inhabitant of 

 Bethune, after he had penetrated through 70 feet of alluvium, 

 and 30 feet of limestone, met with a spring which ascended to 

 the surface; while a neighbour, whose shaft almost touched 

 that of the former, met with no water, although he had pene- 

 trated 70 feet of sand and clay, and then 105 feet into the lime- 

 stone, so that he was altogether 75 feet deeper than his neigh- 

 hour. In the citadel of Calais, they were obliged to carry the 

 shaft to the depth of 1105 yards before pure water was 

 found ; what was met with before this, was saline and brackish. 

 The same is the case in England, where, at least near London, 

 they are not sunk to the chalk ; the depth of the stratum which 

 leads the water is very different. Mile-end is 36, Tottenham 

 70, Epping 340, and HunterVhole 410 feet above the level of 

 the Thames ; and, in the first place, water was found 70, in the 

 second 60, and, in the third, 80 feet above the same level ; but 

 in the last situation, 130 feet above it. — {Conyheare, n. a. p. 36.) 



• De Fonlium Mulinensium admiraiuia scaturignie, of which an abridgment 

 is given in the Act. Erudit. of 1692, p. 505. Also Leibnitz, in his Protogaa, 

 p. 75, expressly speaks of it. 



t Delamcthcrie, Theme de la Terre, t. iv. p. 216. 



