TH je 
M.AGAZJNE; 
OF 
Tf)G mwoi OH AGRiOOLTHKG, 
COLOMBO. 
Added as a 8\q)idement montldij to the TROPICAL AGRIOULTVRISTP 
The following pages include the contents of the Magazine of the School of 
Agriculture for April ; — 
AB,TESIAN WELLS. 
HE most favourable condition which 
renders artesian wells possible is 
a basin-shaped arrangement of 
porous and impermeable strata. 
The surface water flows along 
the line of dip down the porous strata till the latter 
become as it were surcharged like a sponge ; so 
that if a boring were made down to a water-bearing 
stratum of this character, the water which 
had no means of rising through to the im- 
permeable stratum above it, will owing to the 
hydraulic pressure gush out at the surface. 
The following examples are given by Prof. Geikie 
to show the great deptli to which artesian 
wells may be sunk : at Grenelle (Paris) the water 
rises from a depth of 1,771 feet ; at Neusalzwerk, 
near Minden, the depth is 2,394 feet ; at Louis- 
ville in Kentucky, 2,086 feet ; at St. Louis on the 
Missouri, 2,624 feet. Tlie hydraidic pressure 
under which the water is forced to the surface is 
often very great. At Grenelle the fountain as- 
cended at first 112 feet, at Louisville 170 feet. 
The continuity of the typical underground basin 
may be interrupted, and in many cases artesian 
wells merely tap underground waters which would 
otherwise find an outlet to the surface as junction 
springs. 
The advantages of artesian wells are thus set 
forth by Mr. Toushcr of Jlalmeslmry, who under- 
takes to bore and drill artesian wells : — 
1. Because they are bored to such a great 
depth, the depths of the deepest wells being 
usignificfiut. 2. Beciuise they can he bored and 
drilled through strata where it would be impossi- 
ble to dig, for instance quicksand. 3. Because 
there is no necessity to stop at the first water 
obtained, as is the case in dug wells, but that if the 
first water should be brackish or impure, it can be 
completely shut off, and the boring proceeded 
with until the next water-bearing stratum is 
reached, and so on. 4. Because the water 
obtained is always pure, as the artesian well does 
not allow any contaminated water to come in, 
while the waiter in a dug wmll is always more or 
less impure, as, being drainage water, it will 
always (jermit decomposed matter to percolate into 
the well. 5. Because the water is always copious 
and unfailing, being drawn from the underground 
strata, while the wmter in a dug wmll is always 
directly dependent on the rainfall. 6. Because 
they are almost everlasting, not being liable to 
tumble in like a dug well. 7. Because there is 
no danger attached to them. 8. Because they are 
cheaper. 9. Because they can bo bored from the 
bottom of any dug w’ell, no matter how deep, and 
wdiether it contains water or not, and wdthout in 
the least interfering with present arrangements ; 
thus saving the expense of boring to the depth of 
any existing well at any place. Mr. Toiisher as 
an interested wutness to the advantages of arte- 
sian Avells, it may be thought siieaks too disparag- 
ingly of dug wells, but it must be admitted that 
his remarks are in the main w^ell founded. 
Mr. Henry Penning of the Geological Survey of 
England and Wales, waiting on this subject, says 
that the water supply of a district is not by any 
means proportionate to its rainfall — the water- 
bearing beds being great distributors that equalise 
the supply. The supply to be obtained by boring 
dowui to a deep-seated spring, is, he says, practi- 
cally inexhaustible, being rarely, if at all, affected 
by drought, and these springs form the only source 
on wdiich can be placed a full reliance. Keferring 
to the light which geology throws on the question 
of water-supply, Mr. Penning says “ An improve- 
ment in the watei-supply of a district is one of 
the practical results that may be expected to arise 
