the water of the spring in question would necessarily rise to the surface, because, in the well at Elbeuf, which is nearly nine yards above the level of the sea, the water rises from twenty-seven to twenty-nine yards above the surface of the earth, and consequently from thirty-six to thirty-eight yards above the level of the ocean. Now, as the orifice at Grenelle is only thirty-four yards above this same level, it follows that if the same spring were met with, the water must rise above the surface of thev earth at Crenelle. " The necessary works were now commenced with boring-rods about nine yards long, attached to each other, and which could be raised or lowered by mechanical means ;

and an ingenious method was adapted for giving them a circular motion. The diameter of the bore hole was about six inches. The instrument attached to the end of the lowest boring-rod, was changed according to the different strata which were successively reached, the form adapted for passing through the softer materials of the surface, being unsuitable to boring through the chalk and flint, a hollow tube being used for the former, while the latter was penetrated by a chisel-shaped instrument. The size of the rods diminished in proportion to the depth, and as the subterranean water was not reached so soon as was expected, it became requisite five several times to enlarge the diameter of the bore, to admit of the work being successfully continued. Accidents occurred also, which tried the utmost patience of the projectors. In May, 1837, when the boring had extended to a depth of four hundred and eighteen yards, the hollow tube, with nearly ninety yards of the boring-rods attached to it, broke, and fell to the bottom of the hole, and it was necessary to extract the broken parts before any further progress could be made.