FARMERS^ REGISTER— ARTESIAN WELLS. 



451 



OBSKKVATIONS AND QUERIKS RESPJECTIKG 

 ARTESIAN AVELLS. 



To the Editor of the Farmers' ilegister. 



JViliiam and Mary College, Nov. 18, 1834. 



The process of boring for water which of late 

 years has been practiced with so much success in 

 Jiiany parts ul" Europe and tiiis coiintr\-, lius llir- 

 nished scientilic inquirers with an opportunity oi 

 verifying one of tlic most important irutlis wliich 

 modern investigation has disclosed. I alkide to 

 the existence ot very intense lieat at great depths 

 in the eartii, and tlie progressive dnninution of 

 temperature in approaching the surface. This 

 view of the interior condition of Ihe globe, though 

 by no means ot" modern origin, has, until a com- 

 paratively recent time, been deservedly classed 

 with the thousand other speculations concerning 

 our planet, to which the ingenuity and eloquence 

 of theorists have given temporary celebrity. But 

 in the present day, the doctrine has assumed a more 

 imposing attitude. Even in its rcierence to the 

 entire mass of the earth, it is sustained by the con- 

 current evidence of a multitude of facts, while so 

 Jiir as it relates to depths which observation has 

 actually explored, it has acquired the character of 

 established truth. 



It is now very generally admitted, that the tem- 

 perature of the earth, at great depths, is much 

 hiijher than at the surface, and that the increase 

 begins to be perceived as soon as we penetrate be- 

 low the limit at which external impressions of 

 temperature become insensible. The numerous 

 observations which have been made of late years 

 in the mines and Artesian Wells of Europe, have 

 not only established the general fact of an increas- 

 ing temperature, but have determined lor many 

 places in Great Britain and on the Contment, the 

 precise depth at which the augmentation begins, 

 and the rate of increase which subsecjuently occurs. 

 But as yet I believe no observations of a similar 

 nature have been made in this country, though the 

 number and depth of our Artesian Wells would 

 seem naturally to invite attention to the subject. In 

 Western Virginia, Alabama, and some of the 

 Northern States, this investigation might be car- 

 ried on with great success. Nor should it be ob- 

 jected, that these researches are only matters ol 

 scientific curiosity, and that they cannot be subser- 

 vient to any useful purpose. JNIuch that is valua- 

 ble might flow from a careful examination of tem- 

 peratures and other circumstances connected Avith 

 our Artesian Wells. Discoveries bearing upon 

 the economy of these wells have actually attended 

 such researches in some par's ol" Europe, and there 

 are doubdess others still to be achieved. Nor is it 

 unreasonable to expect even useful lights in agri- 

 culture from an accurate investigation of the tem- 

 peratures of the superficial strata of the globe. 

 Already observations of an analogous nature have 

 disclosed the curious and important truth that in 

 high latitudes the near temperature of the earth is 

 less diminished than that of the 3,tmosphere, and 

 hence Wahlenberg, and after him Kuppfer, have 

 explained the fact that many deep-rooted plants 

 and trees attain a vigorous grov>'th in situations 

 Avhere, from the general coldness of the air, it 

 Avould be thought impossible for them to exist. 



In the hope that some of your readers either in 

 our western counties, or in Alabama, may be in- 

 jduced to institute obsen'ations on the salt wells or 



other borings, as well as the ordinary springs in 

 their vicinity, I have drawn up a list of inquiries, 

 embracing several subjects to which their attention 

 might he advantageously directed. It will be seen 

 that only part oi" these relate to the tempzratare of 

 the wells. The others' refer to various points of 

 examination either interesting on account of their 

 [irobable bearing u] on the lornier, or from their 

 own intrinsic imi;ortaiiC3 in a scientific, as well as 

 practical point ot" view. In connection with the 

 enumeration of these several points of inquiry, 

 directions and explanations are added for the ben- 

 efit of" the observer, together with such facts, de- 

 rived from observations abroad, as are likely to 

 furnish a guide to researches in our own couiitr)-. 

 The subjects to which I would here solicit irnesti- 

 gation are embraced in the following queries. 



1. What is the general temperature of the or- 

 dinary springs in the vicinity? 



In reference to this query I would remark, that 

 in comparing the temperatures at different depths 

 in the earth with the temperature at the surface, it 

 is necessary that the mean temperature of the sur- 

 face should first be ascertained. To do this with 

 great accuracy requires a series of observations 

 with the thermometer, continued lor many years, 

 and made at short intervals. But as this could not 

 in general be ex|)ected, an approximation may be 

 obtained, by observing the temperature of the 

 springs, in the neighborhood, particularly, such as 

 issue liom a considerable depth. Of course, much 

 caution will be necessary in the selection of springs 

 lor observation, and in some districts it will be al- 

 most impracticable to find any whose temperature 

 would correspond to the mean of that at the sur- 

 face. - Such a difficulty, for instance, would occur 

 in some neighborhoods among our mountains, 

 where mineral springs of various temperatures 

 abound. But even there the freestone and lime- 

 stone springs which have obtained their steady 

 temperature by percolation tiirough the superficial 

 strata of sandstone and calcareous rock, would ge- 

 nerally fiirnish a very close approximation to the 

 mean. In less broken regions, where the sprino-s 

 are fed from deep strata of gra\ el, sand, and clay, 

 their temperature is uniform throughout extensive 

 districts, and approaches very nearly to the mean 

 of superficial heat. Of course, such springs as 

 will give this mean, must preserve their tempera- 

 ture unchanged throughout the year. If, there- 

 fore, observations made at different seasons, indi- 

 cate any considerable variation in the temperature 

 of a spring, no exact inference as to the mean can 

 be deduced from a single observation. But if the 

 vaiiation be ver)" small, as for instance, one or two 

 degrees at opposite periods ot" the year, the mean 

 may be very closely approached by taking the 

 average or halt-sum of the two extreme tempera- 

 tures. Indeed, this method might f"requently be 

 resorted to with advantage, as a substitute tor nu- 

 merous atmospheric observations. As the impres- 

 sions of" external temperature travel downwards at 

 a very slow rate, Ave should not expect to find even 

 comparatively su|;erficial springs promptly sympa- 

 thising in the changes that occur above. More- 

 over, as these impressions grow fainter in their 

 progress through tiie earth, and at lenglh become 

 entirely imperceptible, the fluctuation of tempera- 

 ture in springs even at a depth of twenty feet ivill 

 present but a small fraction of the corresponding 

 variation at the surface. It appears therefore, that 



