General Haupt, of the United States Army, the engineer-in-chief of this tunnel, is said, by the _Times_, to have invented one of the most compact, effective, and economical drilling machines, applicable for boring tunnels, driving adits of mines, and indeed for every description of work in which the hardest kinds of rocks have to be pierced. It is stated that it can drive holes in granite, or even quartz, at the rate of nearly four inches in a minute, and that as soon as about twenty-eight inches have been drilled, the blasts take place, when the machine can, in consequence of its great lightness and portability, be immediately carried over the _debris_ caused by the explosion, and be at work upon the new face of the tunnel in the course of a few minutes. We extract the “latest novelty” in tunnels from a New Zealand newspaper received in England August 1867,— “A TUNNEL THROUGH AN EXTINCT VOLCANO.—The Moorhouse Tunnel, opening up the fertile plains of the Canterbury settlement, is 2,838 yards long, and cost £195,000. It affords, we believe, the first instance where a complete section of an extinct volcano has been opened out. The elaborate drawings prepared by Dr. Haas for exhibition in Paris, will draw the attention of geologists to the fact, and doubtless afford the greatest satisfaction to the scientific world. The rock in the tunnel may be described as a series of lava streams and beds of tufa, intersected by vertical dykes of phonolite. The lava streams consist generally of scoria, overlaying a coarse pink trachyte, which passes gradually through shades of grey, purple, and blue into a black finely grained dolorite intensely hard and tough; the lightest and softest rock being at the top, and the densest and blackest at the bottom. Regarded from an engineering point of view, the work is considered eminently successful.” The New Zealanders are naturally very much elated at the completion of this, to them, great and important work, of which the _New Zealand Examiner_, a monthly journal published in London, and devoted exclusively to the interests of the New Zealand settlements, thus speaks in its August number:— [Illustration: METROPOLITAN RAILWAY.]