104 On Artesian Wells near Silsoe in Bedfordshire. 



but it remains constant at that level ; whereas the ordinary wells 

 sunk into the surface of the lower greensand, fluctuate in this 

 respect, as might readily be imagined, with every change of 

 season. 



The bore-holes ali-eady executed vary in diameter from two to 

 four inches, and do not require tubing beyond the first ten or 

 twelve feet. Some of the smaller size, of an average depth of 

 about 170 feet, have been put down at a cost not exceeding £7*. 



The water derived from this subterranean reservoir is of a 

 slightly chalybeate nature, depositing on exposure to the atmo- 

 sphere a yellowish slime of hydrated sesquioxide of iron. Its 

 temperature is 51° F. The ferruginous taste is at first strongly 

 perceptible ; but this, of course, becomes less apparent when the 

 water has stood for some time, and I did not hear any complaints 

 in respect to quality from persons in the daily habit of using the 

 water for culinary and other purposes. On the contrary, it was 

 generally considered to be very wholesome. Compared, indeed, 

 to that taken from the brooks, in which organic matter is largely 

 prevalent, the marked superiority of the deep-well water does 

 not admit of the slightest doubt. 



When first drawn, it is beautifully clear, but after the lapse of 

 three or four hours it becomes clouded from separation of carbo- 

 nate of iron ; regaining, however, its transparency on the depo- 

 sition of the precipitate. Mr. Dugald Campbell has kindly ex- 

 amined for me, by Dr. Clark's test, a specimen of this water taken 

 from an overflowing well — shown in the annexed sketch — at White- 

 hall near Wrest Park, on the 

 property of the Earl de Grey. 

 This well is 186 feet deep, 

 with a bore of four inches in 

 diameter. The water gushes 

 out with great force, day and 

 night, in a contin\ied stream, 

 and at the rate of about 76 

 gallons a minute. 



The following are the results obtained by Mr. Campbell : — 



Hardness . . . 9°-38 



Alkalinity . . . 8°-50 

 It is difficult to arrive at any very accurate conclusions as to 

 the quantity abstracted daily from this subterranean source ; but 

 judging from the number and power of the overflowing wells, 

 and from a fair estimate of the amount drawn from those which 

 do not overflow, there must certainly be a daily consumption or 



* On tlie authority of William Arnold of Greenfield, by whom the greater 

 part of the deep wells in this district were bored. 



