452 



FARMERS' REGISTER— ARTESIAN WELLS. 



a few observations, made upon sjjrings, will be of 

 greater use in determinino; the mean nnnual tem- 

 perature of a place, than a great number, made in 

 the ordinary way, by exposing the thermometer to 

 the air. In reierence to this topic, it may be re- 

 marked, in conclusion, that the determination of 

 this mean is far from being laiimportant to the ag- 

 riculturist; for it contributes a large item to his 

 knowledge of climate, and as we all know climate 

 is continually influencing the results of his opera- 

 tions, and sliould be thoroughly understood, to se- 

 cure them the highest attainable success. 



2. What are the general features of the sur- 

 rounding country? 



3. What rocks show themselves in the neigh- 

 borhood, and how are they disposed? If, inclined, 

 in what direction do they dip? 



4. Through what strata does the well or boring 

 penetrate, and what is the thickness of each stra- 

 tum? 



The investigations here suggested, though des- 

 titute of any immediate practical use, of which the 

 farmer might avail himself] are, nevertheless, of a 

 nature to interest him li'om the light which they 

 may throw upon the origin and peculiar character 

 of the springs and Artesian Wells in his vicinity. 

 In a geological point of view, they are of the ut- 

 most importance, and such is the growing connec- 

 tion between geology and agriculture, that what- 

 ever promotes the one must either now, or at some 

 future day, contribute to the advancement of the 

 other. 



5. To what height does the water nse in the 

 well, and is its height uniform or fluctuating? If 

 the latter, in what conditions of the weather, or 

 other influencing circumstances, does it rise and 

 fall? 



6. What is the character of the water? Is it 

 like that of the common springs in the vicinity, or, 

 if not, in what respects is it peculiar? 



7. Is any gaseous matter discharged with the 

 water? If so, what is its nature? 



A chemical analysis of the gas thus evolved, 

 would not, in general, be practicable, but the de- 

 termination of one or two of its most obvious pro- 

 perties would not be attended with any great dilfi- 

 oidty, and might suffice to determine its nature. 

 Thus its odor, if it possess any, its effect upon a 

 lighted taper, its absorbability by cold water, and 

 its etiect upon the color of a slip of paper mois- 

 tened with a solution of sugar of lead, would be 

 matters of very ready observation. 



8. What is the temperature of the water at the 

 BurPdce, and at successive depths of 50, 100, 150, 

 &c. feet? 



Allusion has already been made to the interest- 

 ing fact of an increased temperature at great depths 

 below the surface of the earth. This increase, as 

 was belbre intimated, does not begin until we pass 

 the limit at which the impressions transmitted 

 from the surface become insensible. Of course, 

 the distance of this limit from the surface, will 

 vary with the nature of the intervening strata, be- 

 ing greatest always in those soils which most rea- 

 dily transmit the temperature from above. Ac- 

 cording to the observations which have been con- 

 tinued for tlie last fifty years in the caves beneath 

 the Observatory in Paris, the temperature at the 

 depth of eighty-three feet, has. during this long 

 period, remained perfectly uniform; being by the 



Centigrade scale, 11.82 degrees or 53^^ 27 by that 



of Fahrenheit. 



Comparative observations at depths of from one 

 to fifteen feet, have been made at Edinburgh, Stras- 

 burg and Zurich, and the mean temperatures at 

 the&e de|)(hs ascertained for each month in the 

 year. From these it would appear, that even at 

 the depth of a few feet the annual variation of 

 temperature is very much reduced. Thus at 

 Edinburgh, the mean temperature of the hottest 

 month by a thermometer in the air, being 59° 36, 

 and that of the coldest by the same instrument 

 38° 3, the corresponding mean temperatures at 

 the depth of eight feet below the surface were 

 respectively 50° and 42° — thus giving for the an- 

 nual variation on the- surface 20°, and for that at 

 eight feet below only 8°. Again at Strasburg, the 

 warmest month having a mean of 62° 6, and the 

 coldest of 28° 4 at the surface — these means at 

 the depth of fifteen were respectively 52° 8 and 

 43° 8 — giving an annual variation at this depth 

 but little exceeding one-fourth of that at the sur- 

 face. 



In looking over these observations, it is interest- 

 ing to remark the successive arrival at a given 

 depth of the impressions of temperature from 

 above, long after these impressioi^s have declined or 

 ceased upon the surface. Thus, even at the depth 

 of eight feet, the highest temperature is not ex- 

 perienced until September, and the lowest until 

 February. Winter and summer, as it were, ar- 

 riving a month or more after they have occurred 

 above. 



It is obvious from tliese statements, that changes 

 of season become imperceptible at a comparatively 

 small distance beneath the soil, and that the cli- 

 mate of the earth at the depth of 50 or 100 feet is 

 perf(3ctly uniform throughout the year. Hence 

 springs issuing from this region may be expected 

 to present little or no variation in their tempera- 

 ture. Beneath the depth at which this uniformity 

 first becomes manifest, it has already been said, 

 that the temperature progressively increases as 

 we descend. A statement of some of the evi- 

 dences by which this curious law has been estab- 

 lished, may not prove unacceptable or useless to 

 such of your readers as are interested in the ob- 

 servations to which this communication particidar- 

 ly refers. 



Gensanne, who was the first to experiment upon 

 the comparative temperatures at different depths, 

 obtained in the lead mines of Giromagny the fol- 

 lowing results. 

 At a depth of 101 metres the temperature was 



12° 5 Centigrade. 

 206 " 13 1 "^ 



308 " 19 <' 



433 " 22 7 " 



Sanssure in the salt pits of Berne found at a depth 

 of 108 metres, a temperature of 14° 4 Centigrade 



183 " 15 6 " 



220 " 17 4 '■• 



The observations of Cordier, a celebrated French 

 geologist, being among the most complete and 

 satisfactory that have yet been published, may 

 with propriety be here transcribed. They were 

 made in the three great coal mines of Carmeaux, 

 Littry and Decise, and the temperatures were ob- 

 tained both from the rocks and springs al different 

 depths. 



