PART 4.] Center: Note on Heh or Alkali Soils and Saline Well waters. 
259 
correct way is to perform an experiment similar to wliat I have described before 
with the glass funnel. A zinc box is made open at the top and closed at tho 
bottom, with a false bottom of perforated zinc half way down. The section is 
usually 1 square foot. Earth is placed above the perforated zinc, and the whole is 
exposed to the varying conditions of the season and climate, as rainfall, heat, 
moisture, &c. All water that falls sinks through the perforated bottom, and is 
collected or evaporates. After some months or a season tho solution in tho 
bottom of the box and the earth are examined in the usual way to find tho 
results of decomposition. Such an instrument is called a Lysimoter, and ha.s tho 
advantage of demon.strating the changes that take place, not by tho action of 
acids, but by the ordinary operations of natui'o. 
14. Another source of generation and accumulation of these salts takes place 
Underground produc- in tlie strata moistened by tho underground water. Thi.s 
tion of salts. is pai-tly derived from percolation of rainfall from tho 
surface where it is sufficiently porous. In its passage downwards it washes out 
any soluble salts it meets and carries them down till it roaches tho impermeable 
stratum. In the second place tho air contained in the vegetable mould and 
porous ground is rich in carbonic acid, and this is absorbed by the water and 
enables it to dissolve more lime and magnesian carbonate, which accounts for 
the much greater hardness of subsoil waters. In tho third place the alkaline 
water charged with carbonic acid not only promotes the decomposition of tho 
strata through which it filters, but by a con.stant soakage action on that which it 
moistens produces still more. Tho amount produced would be in a great mea¬ 
sure proportional to the time the water remains in contact with the stratum. In 
stagnant underground waters in the middle of tho plains, as at Chunga Manga 
and Wanradaram, the dissolved salts amount to 400 grains per gallon. Another 
feeder of the underground water is the percolation of hill water that sinks into 
the porous fringe at the base of the hills. This, however, aSects particularly 
the plain near the base of the hills. The solution formed from the debris on tho 
hillside is much less saline than that from the finely-divided and more degraded 
materials of the plain. The hill percolation therefore affects the underground 
water near the hills in two ways. It raises its level by hydrostatic pressure and 
it makes it less saline by dilution. There is still another source of underground 
waters in the jrercolation from rivers, streams, and canals. The neighbourhood 
of rivers affects the water-level, and very sensibly influences the quality of the 
subsoil water. Analyses of waters taken from wells near them show that they 
closely approximate to the river waters, being little more than those filtered. 
For examj)le, the well water near the Ravi was found to contain from 8 to 
15 grains per gallon, that near the Jumna 9’8 to 14 gi'ains. Advantage is now 
being taken of this in supplying water from such wells to some large cities in the 
Punjab. The influence on the quality of the subsoil water, however, only exists 
in the khadar land, or low river valley. In the bhangar, or bar land, the 
upland that lies between neighbouring rivers, even at short distances from the 
valley, the water may be highly saline. In the case of canals, as far as my ob¬ 
servation goes, there is very little percolation in the districts I have seen irrigated 
by the Bari Doab Canal, on account both of the impermeability of the soil and 
