398 THE POPULAR SCIENCE MONTHLY. 



channels, either containing water alone or water filling the interstices 

 of some porous material, these waters being the product of rainfall, 

 dew, and snow. But this answer has sometimes been found not to 

 satisfy a certain class of minds ; and, as long ago as 1834, Arago 

 thought it not beneath him to publish in the " Annuaire du Bureau 

 des Longitudes " for 1835 a considerable essay, in which he shows con- 

 clusively that the rise and flow of water in springs and artesian wells 

 are sufficiently explained by the cause assigned above. Further on 

 will be found a translation of some passages from this elegant essay. 



Arago was so certain of the correctness of his views, that from his 

 knowledge of the geological formations of France he not only fore- 

 told that potable water would be found by boring an artesian well at 

 Grenelle, near Paris, but that the water would rise and overflow the sur- 

 face. In 1833 he succeeded in getting the French Government to un- 

 dertake the boring of this well, and although about eight years were 

 required to complete it and it was for some time in danger of being 

 abandoned, his urgent representations prevailed in obtaining a further 

 prosecution of the work, and in 1841 his foresight was rewarded with 

 the splendid success familiar to the public. Modern engineers, in judg- 

 ing of the chances of getting flowing water from an artesian well in 

 any particular locality are guided by the same general theory as that 

 held by Arago. 



But a writer in the November number of this magazine combats 

 this theory, " not merely from speculative motives, but in the interest 

 of public health," and ofl^ers an explanation of his own, involving a 

 " newly discovered force " which " not only may, but which positively 

 must, force waters out of springs at high elevations." This " new 

 force" as it is called in another sentence, is "the resultant of the 

 earth's centripetal and centrifugal forces," and it produces springs and 

 flowing wells by acting *' impulsively upon the subterranean water de- 

 posits," tending " to force them into and though the natural channels of 

 the earth's crust." It is proposed here to examine Mr. Green's article 

 in some detail, in connection with a consideration of the generally 

 accepted theory of springs and flowing walls. 



A peculiarity in one or two of Mr. Green's quotations led me to 

 verify them in the works cited by him, and in doing so I could but 

 notice that he had apparently made a number of slips of the pen, 

 which, though perhaps unimportant in themselves, yet give indica- 

 tion of some carelessness. For instance, in quoting from " Littell's 

 Living Age," he changes Golne to Coin, Watford to Wetford, Pole's 

 Hole to Pales's Hole, Dickenson to Dickinson, Canstadt to Constadt, 

 Bruckman (which should have been Bruckmann) to Buckmann, and 

 predicted to discovered. Another of his quotations from the same 

 source is this, "The artesian well at Tours rose with a jet that sus- 

 tained a cannon." The original said, "An artesian well at Tours rose 

 with a jet that sustained in the air a cannon-ball." As the account of 



