. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. THE GREAT ALPINE TUNNELS. 619 2 feet in width. :ukI ;^ feet in height, except at the probable point of meeting, where the height is 4 feet 6 inches. The length is 1,708 feet, and there is a fall of 1 foot in this distance. About the middle of its course there are apparently two false cuts, as if a wrong direction had been taken; but possibly these were intentional, and provided passing places for the workmen and material. On the soffit of t
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. THE GREAT ALPINE TUNNELS. 619 2 feet in width. :ukI ;^ feet in height, except at the probable point of meeting, where the height is 4 feet 6 inches. The length is 1,708 feet, and there is a fall of 1 foot in this distance. About the middle of its course there are apparently two false cuts, as if a wrong direction had been taken; but possibly these were intentional, and provided passing places for the workmen and material. On the soffit of the tunnel is carved an inscription, of which the fol- lowing is a translation: "Behold the excavation. Now this had been the history of the excavation. While the workmen were still lifting up the pick, each toward his neighl>or, and while 3 cubits (1 feet 6 inches) still remained to cut through, each heard the voice of the other, who called to his neighbor, since there was an excess of rock on the right hand and on the left. And on the day of the excavation the workmen struck each to meet his ncight)or pick against pick, and thei'e flowed the waters from the spring to the pool for 1,200 cubits (1,820 feet), and 100 cubits (151 feet) was the height of the rock over the head of the ; A Roman engineer gives an account of a tunnel which was being driven under his directions for an aqueduct. And as he was only. (/VoC Co Scait^ Fir;. '2.—Plmi of Tuniu'l from Spring to Pool of Siloam. able to visit the work occasionally, he describes how on one of his visits he found the two headings had missed each other, and he sa3's that had his visit been deferred much longer there would have been two tininels. The accurate meeting of the headings or driftwavs of a tunnel can only be attained by the exercise of great care, both as regards direc- tion as well as level. We need not go ver}' far to tind instances of such an error as inac- curate meeting, but there is one well-k
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