THE HYDROGEOLOGY OF THE PLYMOUTH DISTRICT. 105 
ON THE HYDKOGEOLOGY OF THE PLYMOUTH 
DISTRICT. 
BY MR. JAMES C. INGLIS, A.I.C.E. 
(Read January 25th, 1877.) 
The term Hydrogeology, at a recent meeting of the Institution 
of Civil Engineers, Mr. J. Lucas denned as follows : 
"It was first used by the author in 1874, and takes up the 
history of rain-water from the time that it soaks through the 
soil, and follows it through the various rocks which it afterwards 
percolates." Mr. Lucas further explains: "A Hydrogeological 
survey comprehends an examination of all facts bearing on the 
form and position of subterranean water systems, and in basins 
where they are covered by superincumbent strata, the extent to 
which they are syphonised, together with other particulars tending 
to show their general capabilities for supplying water." 
Somewhat lately the interest in this subject, the circulation of 
rain-water, has revived, and at the present moment it commands a 
large and increasing number of students in France, Germany, 
Italy, and England. In this country sanitary questions have been, 
and still are, a source of great vexation of spirit and intellect to 
many a municipal officer ; so much so, that our largest assembly, 
the Council of the Nation — Parliament — resounded with the watch- 
word, " Sanitas sanitatum omnia sanitas" not so very long ago. 
The agitation has had its good results, mostly in seriously drawing 
attention to the points at issue. This revival, then, of drainage, 
sewerage, and similar questions affecting the collective health, is due 
entirely to one of those stern reminders necessity every now and 
then gives us. 
Hydrogeology, as we have seen, claims all the literature on rain- 
water after its fall, and as long as it remains underground. When 
on the surface, flowing or remaining stationary in masses, its study 
is what is ordinarily understood by Hydraulics and Hydrostatics. 
