ON THE CIRCULATION OF UNDERGROUND WATERS. 381 
portions.’ In reply, Mr. Roberts writes, ‘I would immediately have set 
to work to verify the results which I had obtained seven years ago; 
but after studying Mr. Ripley’s methods of research, and his inferences, 
I do not find that he has proceeded on lines that are even approximately 
reliable as tests of my results.’ He asks, ‘Is it proof, or reasonable in- 
ference, that, because Ohio stone, which contains salt in its pores, does not 
filter salt from water, neither, therefore, does Triassic sandstone, which 
does not contain salt, from Everton [Lancashire], filter any ?’ 
It is therefore necessary for Mr. Ripley, to establish his position, to 
repeat his experiments with sandstones which either contain no salt or 
from which it has been totally removed. He gives no record of such an 
experiment in his paper, and Mr. Roberts’s experiments remain unassailed. 
Mr. Roberts draws attention to the hygroscopic properties of the New 
Red Sandstone, or its power of rapidly absorbing moisture from the 
atmosphere and giving it off again on any increase of temperature. Four 
years ago he selected a cube of Bunter sandstone, and depriving it of 
moisture, weighed it, and found the weight 14,553 grains. This weight 
he adopted as zero. On exposing the stone freely to the air it rapidly 
and steadily absorbs moisture, varying from hour to hour with the 
changes in the humidity. In June, 1883, its weight of moisture varied 
between 38 and 74 grains, in December of that year it varied between 
73 and 107 grains. 
Details of Wells and Borings, Berkshire. 
Swindon Local Board Well. Mr. R. W. Mylne, C.E., F.R.S., Engineer ; 
Mr. R. Spellor, Blackfriars, London, Contractor. Works consist of a 6-feet 
shaft of 110 feet depth, with boring to 500 feet below the top of the shaft ; 
at the bottom of the shaft is a chamber of 14 feet, from which is driven 
an adit level to the side of the hill, tapping the water met with at the 
bottom of the shaft. 
Details and Specimens collected by C. BE. De Rance. 
From surface Thickness 
feet feet 
107. Chalk . : : : : : ‘ : , 4 PLOs 
110. Sand (upper greensand) : - : é : 3 3 
248. Grey clay (gault) . 3 A : 3 E ; sfh3s 
250. Grit (lower greensand ?) : ; . : . F 2? 
322. f Grey clays, harder 310 feet from surface - 72 feet) 250 
500. | Shelly clays (boring discontinued) so whZS) 55. fi 
500 
Comparing these thicknesses with those given in the Horizontal 
Section of the Geological Survey traversing this area, it is probable that. 
the 250 feet of clay below the grit all belong to the Kimmeridge clay. 
Geological Survey Swindon Section 
feet feet 
Upper greensané ¢ : - 60 : ; 5 3 
Gault F : : : . 140 d . - 138 
Lower greensand . ‘ . 40 Z ) 7 2? 
Kimmeridge clay . = - 280 : : . 250 
Coral rag . : ; ; . 40 
Oxford clay . 3 , - 500 
