346 
Farvihig of Hampshire. 
he necessary to perfect tlie works in the areas A and C as has 
been already done in area B. By daily records of the height of 
water in test-holes, it has been there shown that the standiiu/ 
water level does not approach within 4 feet of the surface, though 
the fluctuations of height follow the rainfall with exactness ; and 
by measurement of the discharge it is found that the saving of 
water from evaporation in favour of the river supplv is from 50 
to 90 gallons per minute during the summer season. 
J. Bailey Denton. 
3. LETTER FROM LORD PALMERSTOX. 
The following letter, written by Lord Palmerston, in reply to 
a request made to him by Mr. Bailey Denton, that his Lordship 
would state his opinion as to the influence of the recent drainage 
works, on the climate and water-supply of the Test Valley, will 
be ready with interest : — 
My dear Sir, Piccadilly, 6tli January, 1862. 
I HAVE received your letter of to-day. The question to 
which it relates seems to me to be as clear and as simple as any- 
thing can be. 
It is demonstrable that under-draining must render more dry 
the atmosphere of the lands drained, and it is equally plain that 
it cannot materially, if at all, diminish the supply of water to 
any river that flows through such lands. Undrained land is like 
a sponge ; it is saturated with the moisture which, by capillary 
attraction, it draws up from below, and with the moisture which, 
in certain conditions, such as sea-fog, it imbibes from the atmos- 
phere, and with the water which falls in the shape of rain or 
snow. The moisture thus held by this spongy upper stratum of 
the land is got rid of mainly by evaporation into the atmosphere 
in contact with such land ; and the quantity of water with which 
that atmosphere is thus charged is in some cases very consider- 
able, and l)cing much greater than the air can hold in solution, 
it is precipitated in the shape of mist and fog, to the detriment 
of the health of the inhabitants of the district. The effect of 
sufficient undei-draining is to convert four or five or six feet of 
the upper crust of the land from the condition of a sponge to 
that of dry earth. That thickness of crust no longer draws 
moisture from below by capillary attraction, and the water which 
falls upon it as rain or snow, or which is deposited upon it by 
sea-fogs, instead of rising into the atmosphere by slow evapora- 
tion, finds its way rapidly into the drains, and is carried off by 
them. The soil would, however, always by its retentive nature, 
