Two cases in point are before me as I write; in the one 15,000l. has been spent in sinking a shaft and driving headings which yield but little water, found abundantly at the same depth in a mine adjoining; and in the other a town would be, but for its surface wells, entirely without water, the waterworks having been idle for weeks, and the sinkers are feebly endeavouring to obtain water by deep sinkings, in a position where its occurrence in any quantity is physically impossible. Ample supplies could be obtained in both these cases by shifting the situation a few hundred yards.
The subject-matter of the following pages is divided into chapters which treat of geological considerations, the new red sandstone, well sinking, well boring, the American tube well, well boring at great depths, and examples of wells executed and of localities supplied respectively, with tables and miscellaneous information. Each system with its adjuncts has been kept complete in itself, instead of separating the various tools and appliances into classes, the plan adopted in the most approved French and German technical works. This, however, when too rigidly adhered to, as is the case with German works in particular, renders it troublesome for even a practised engineer to grasp a strange system in its entirety, while the pupil is wearied and retarded in his reading by an over-elaborate classification.
It may, perhaps, be remarked that undue prominence has been given to the tertiary and cretaceous formations, but it is urged in extenuation that they happen to underlie two of the most important cities in Europe, and that they have, in consequence, received a more thorough investigation than has been accorded to other districts. The records of wells in many formations are singularly scanty and unreliable, but it is hoped that the time is not far distant when the water-bearing characteristics of strata, such as the new red sandstone and permian, will receive proper attention, and that correct official records of well-work will be found in every locality, as this alone can rescue an important branch of hydraulic engineering from the charge of empiricism.
In the course of the work the writings of G. R. Burnell, C.E., Baldwin Latham, C.E., M. Dru, Emerson Bainbridge, C.E., G. C. Greenwell, and other well known authorities, have been freely referred to, particular recourse having been had to the works of Professor Prestwich, F.G.S.
I am indebted to Geo. G. André, C.E., F.G.S., Messrs. S. Baker and Son, and Messrs. T. Docwra and Son, for many suggestions and much valuable information; to Messrs. Docwra special thanks are due for some of the important sections illustrating chapter vii.
Any claim to attention the book may deserve is based upon its being an attempt to embody, in a collected form, facts and information derived from practice, or from various sources not accessible to the majority of those engaged in the superintendence, or otherwise interested in the construction of wells.
ERNEST SPON.
16, Craven Street, Charing Cross,
June, 1875.