3i4 
Scheme of Water Supply. [July, 
accept advice from amateurs, of whose mode of observation 
and process of reasoning they were generally ignorant. But 
the maps of the Geological Survey, published under the 
authority of a Public Department, and showing the limits of 
the water-bearing and impervious formations laid down with 
the greatest attainable accuracy, furnish ready to hand all 
the data for determining the preliminary questions. With 
these maps a Sanitary Board ought to be able, with very 
little assistance of a technical kind, to determine whether a 
particular village or hamlet, requiring good water, was so 
placed geologically as to be able to obtain a supply by means 
of a well ; and, if so, also the best spot in which such a well 
should be sunk. 
I am aware, however, of the unhappy and prevalent igno- 
rance of even the most rudimentary principles of geology 
amongst such bodies, and it would therefore be necessary — 
for the proper carrying out of the proposals here suggested 
— that an experienced geologist should be attached to the 
staff of the Central Board of Health in London, whose duty 
it should be, when applied to, to afford advice in all cases 
of this kind. Owing, therefore, to the progress of the 
Survey over the districts here alluded to, it seems to me 
that the time has arrived for putting in force some scheme 
of general application depending on geological considerations. 
Cases not admitting of Supply by Means of Wells . 
I now come to the case of those villages, hamlets, or 
parishes which, owing to their geological position, cannot be 
supplied by means of wells. These are they which are 
situated on such impermeable strata as the Oxford Clay, the 
Lias or the Keuper Marls, or are at such a distance from the 
subjacent water-bearing strata that the depth of a well 
would be great, and the expense too costly for the resources 
of the inhabitants. In such cases a supply from surface 
drainage of some available brook or rivulet seems the only 
resource ; and powers should be given by the local sanitary 
authority to impound such stream in small reservoirs, under 
proper and stringent regulations, so as to prevent surface 
pollution of the water either in the stream or in the reser- 
voirs. The construction of such small reservoirs as would 
be necessary for the purposes here alluded to would entail 
only a moderate amount of engineering skill and of pecu- 
niary outlay. In providing pure water it would also be 
necessary to stop up or destroy all impure wells, pools, or 
tanks, in the same village or hamlet, as the poor are very 
