xevi Proceedings of the Asiatic Society of Bengal. [N.S., XV, 
At the top of a ridge the soil Piha ig is red in colour oe Nag bin, 
and lies directly on the very permeable substratum: dow. e sides 
the ridges the soil deepens bo th i oe snag our snag depth, sad, a a 
: - - : 
i n 
conditions arise, and the vac ome rae nse nnot aa away is forced 
uu 
portions until the pan Stk ey carries 0 3 perder 
If we bore a hole in a salt area we do not find subsoil water near the 
surface, and it is not till we pierce the moderately a subsoil 
layer at about 5 to 10 feet that Sar rushes in with a hissing noise. 
e permeability of the permea ble cde is eananearet by the rate of 
recuperation in the bore holes by the formula 
- 1 Glo H 
a= le FT 
where K = Coeffici 
T = Time in bee 
bs Sa head of seer 
he of leona a ahs T hours. 
Unfo iS this only eae us a measure of the permeability of the 
wih 2a does not necessarily show that it is a main avenue of drainage. 
n supply may come 5 heir fissures at a great depth, and pos- 
ably thon ugh rock. 
e essential point is that we are dealing with a pressure ; hence 
The 
very open risegend of the problem e permeable subsoil — not 
be looked on as an avenue for drainage but merely as a medium through 
which the deep subsoil-pressure is di 
What we have to do, pric is o find out ae natural deep 
sierap rd the original denuded valleys nai open thorn 6 + down to the 
a 
ery ratory ver: nalas do not follow the natural drainages, 
and Mot seldom 
Where the permeable stratum is at such a depth that a drain reach- 
ing down to it is out of the question, see ean still be done by driving 
down bore holes rane “this saubnes, when the water rises per pressure 
and can be carried away in a pipe drain. 
The frequent failure of a large sisal of the rice crop 
in Chota Nagpur.—By A.C. BS. 
The soil of the Chota Nagpur — ame for - most part on solid 
neissic rocks, and the subsoil water i rived from the local psc 
essation 
° } se 
rraces therefore fester to the point of cracking about a fortnight after the 
last shower. is eherstore safe only on the concave surfaces of 
