PART 2.] 
King : on the Artesian Wells at Vondieherry. 
119 
The behaviour of the 
water sheets. 
Above first imperme¬ 
able seam. 
strata hading up still further to the west on the shores of the great Oussandan 
tank west of Pondicherry. 
The permeability or otherwise of the beds is very clear in this boring: no 
sooner is fair clay reached and pierced than the tube 
(filled with water from the .sand above) is gTadually 
emptied, until sand is again reached, when water again 
appears.^ A sheet of water, or a seam charged with water, was, however, struck 
at 54'38 feet, which rose in the tube and ran over at 3'28 
feet below the surface of the soil, still above se^ level 
and also above the level in the surrounding wells ; so that 
here was water clearly under pressure of some kind. The seam of sand and clay 
being, however, very thin, the boring was pushed on through the succeeding clay, 
until at 62'32 feet a second sheet was found to rise 
Below the l.st seam of inches over the soil, and after a short time to 17'5 
clays. ’ 
inches. However, as the boring progressed, the water 
fell again 3'28 feet below level of soil, and then an accident occurred to the 
tubing which necessitated the starting of a new boring at 2 feet to one side. In 
the new hole similar strata were passed through, and at 72‘16 feet, water at last 
rose to 15'60 inches above the soil. 
The curious feature in the progress of these two borings only 2 feet apart, 
—that in about 26 feet of coarse sand without any clay the water first rose 
over the soil, then gi-adually fell to nearly 3 feet below the surface, and 
finally rose again to nearly I'S feet over the surface,—is attributed by Mr. 
Poulain to faultiness in his first tube, which he thinks was not quite staunch at 
the rivetted joinings.^ 
A third seam of permeable material (E)was again met at 108'23 feet of 
In the 2nd band of about 3'5 in thickness, which gave a discharge of water 
clays. at 35 inches above the soil, but the boring was continued 
in the hope of obtaining a better flow. 
At 118 feet, a 3-feet seam of sandy material only allowed of water rising 
to within a little more than 2 feet of the surface. It is not clear whether 
sufficient time was allowed here for the water to rise higher, as it ought to have 
done, even though retarded through a more compact condition of the sand. 
After this came 29 feet of impermeable clays (11), from below which water rose 
Below tlie 2ud band of ^ feet above the soil and then fell to 27'30 inches below 
clays. that level. 
The auger now passed through a more varied set of generally arenaceous beds, 
without any definite seams of clay or other impermeable materia l, yet the water 
rises and falls in a remarkable manner, though ultimately, at the bottom of this 
series, the point is reached from which the present fine flow of the Savana well 
rises. There are altogether some 25‘35 feet of these sandy beds. After entering 
on this series, the water mounted slowly and stopped at 11’70 inches over the 
soil: afterwards it rose as high as 19'5 inches when (as graphically expresed by Mr. 
' The fact would require that some permeable beds are quite cut off from the artesian (or any 
other) source, and are still unsaturated, if the ^vord ‘ emptier’ is to be taken literally. 
- The. explanation would suggest that the phenomenon only occurred in the first boring. 
