THE DIVINING ROD. 
119 
Before proceeding further with an account of the experiment 
we may consider the nature of the case we are about to try. It 
is the prediction of a practical man, skilled by experience, 
opposed to that drawn from the generalisations of science. 
The dowser predicts that in one of the pits now to be sunk 
we shall find water, let us call that the + well ; in the other we 
shall not, we will call that the — well. As a geologist I predict 
that we shall find water in both or neither. The dowser does 
not give reasons for his prediction ; for mine they are tlie 
following. 
The field we have selected for the experiment is part of the 
great alluvial flat w^hich borders the eastern side of the Severn 
and Bristol Channel. Sinkings have frequently been made in 
various places through this flat, and have revealed the nature 
and arrangement of the sediments composing it. As a rule 
i^vide comparative sections of Plate) the upper 15 or 20 ft. of 
the alluvium consists of fine silt or clay, beneath which lies a 
bed of peat of variable thickness ; this is underlaid again by silt, 
which at a depth of 20 or 30 ft. contains a large proportion of 
sand, sometimes, indeed, consists altogether of sand ; and beneath 
this, finally, gravel is frequently encountered, but not always, for 
the distribution of the gravel is very irregular, so much so, that 
it is impossible to predict whether it is absent or present below 
any particular spot. Beneath the alluvial deposit any of the 
older rocks may be found ; in the case of that at Locking it is 
almost certain, however, from the structure of the country, that 
the “ bottom ” rock is Triassic. 
The pervious beds of gravel always contain w^ater, and if the 
sinkings at Locking enter this rock, water will assuredly be 
found. If not, it will not be obtained in large amount. It is 
unlikely, how^ever, that gravel should be found in the + well and 
not in the — well, which is only 1 5 ft. distant. Still, considering 
its irregular and patchy ” distribution, there is just a chance it 
