72 THE POPULAR SCIENCE MONTHLY. 



England, was invited, on account of his learning and character, to give 

 an address, in which he made the following statements : * " Wells 

 sunk to a greater depth through stratified rocks often afford large 

 supplies, but rarely rise to the surface ; and in cases where they do 

 so they are called artesian wells, from the circumstance of such arti- 

 ficial flowing wells being common in Artois (France). In all these 

 cases [among which the Professor included the flowing wells at Gre- 

 nelle, near Paris] the water was forced up by hydrostatic pressure to 

 various distances from the surface. At Brentford, England, there 

 were many wells that continually overflowed their orifice, which is a 

 few feet only above the Thames. In the London wells the water rises 

 to a less level than in those at Brentford." 



By hydrostatic pressure, the Professor, of course, means a head, 

 i. e., that the water flowed to these wells from a higher point. If this 

 rise were due to hydrostatic pressure, why did the water rise to a lower 

 level at London than at Brentford among the hills? Professor Buck- 

 land continues : " In November, 1840, notice was given of an applica- 

 tion to Parliament to obtain a new supply of water for London from 

 wells and water- works to be made at Wetf ord in the chalk-hills. A 

 company had been proposed to effect this object, which would probably 

 have been carried out, had not Mr. Clutterbuck demonstrated, by a 

 long-continued series of measurements of the water in the chalk-hills 

 of Hertfordshire, near Wetford, that every drop of water taken from 

 that neighborhood would have been abstracted from the summer and 

 autumn supplies of the river Coin and would have robbed the jDropri- 

 etors of more than thirty mills upon this river and its tributaries, and 

 the owners of adjacent water-meadows, of rights they had had from 

 time immemorial. One intelligent manufacturer, Mr. Dickinson, had, 

 during many years, found arithmetical evidence that the quantity of 

 summer water in the river Coin varied with the rain in the preceding 

 winter. He could always tell, at the end of February or March, what 

 water there would be in the following eight or nine months ; and he 

 regulated the contracts he made in every spring, for paper to be deliv- 

 ered in the summer and autumn, by the quantity of water in his win- 

 ter rain-gauge. This rain-gauge, the invention of Dalton, being buried 

 three feet below the surface, showed that except in December, Jan- 

 uary, and February, rain-water rarely descended more than three feet 

 below the soil, so as to add anything to the supply that sinks into the 

 earth to issue during summer, and from springs and rivers; and, when- 

 ever Mr. Dickinson found by this instrument that but little rain had 

 fallen in the three months of winter, he proportionally limited his con- 

 tracts for the following summer and autumn, thus proving the practical 

 advantage of inductions from j^hilosophy." 



The following abstract from Professor Buckland's speech may also 

 be in order : " As persons who have no experience in these subjects 

 * Copied into vol. iii., p. VO, of " Littell's Living Age," from the " Edinburgh Journal." 



