that put out the lights; six of the workmen were lost. For some distance, Mr. Brunel, junior, struggled in total darkness, and the rush of the water carried him up the shaft. The Tunnel was again cleared, and the part completed found to be sound. Hundreds of plans were proposed for its completion; the funds of the company were too low to proceed, and above 5000_l._ was raised by public subscription. For seven years the work was suspended; but, by advances from Government, it was resumed in 1835. On April 23, 1837, there was a third irruption of the river; a fourth on Nov. 2, 1837, with the loss of one life; and, on March 6, 1838, the fifth and last irruption took place. Thus, of the tunnel there were completed-- In 1836 117 feet. -- 1837 28 " -- 1838 80 " -- 1839 194 " -- 1840 76 " Leaving only 60 feet to complete. Meanwhile, the tunnel works proved a very attractive exhibition. In 1838, they were visited by 23,000 persons, and, in 1839, by 34,000. By Jan. 1841, the tunnel was completed from shore to shore--1140 feet, and Sir I. Brunel, on Aug. 13, was the first to pass through. On March 25, 1843, the tunnel was opened to the public, with a demonstration of triumph. The cost of the work has been nearly four times the sum at first contemplated; the actual expense being upwards of 600,000_l._ These, of course, are but a few data of the great work, the progress of which, for twenty years, interested every admirer of scientific enterprize. The engineering details present marvels of ingenuity. The building of the vast brick shaft, 50 feet in diameter, 42 feet in height, and 3 feet thick, with, set over it, the steam-engine for pumping out the water and raising the earth--and the sinking of the whole, _en masse_, into the Rotherhithe bank, were master-works of genius. Thus far the vertical shaft: the tunnel itself commenced with an excavation larger than the interior of the old House of Commons. But the great invention was the _shield_ apparatus--the series of cells, in which, as the miners worked at one end, the bricklayers formed at the other the top, sides, and bottom of the tunnel. The dangers, too, were many: sometimes, portions of the frame would break, with the noise of a cannon-shot; then alarming cries were heard, as some irruption of earth or water poured in; the excavators were, however, much more inconvenienced by fire than water--gas explosions frequently wrapping the place with a sheet of flame, and strangely mingling with the water, and rendering the workmen insensible. Yet, with all these perils, but seven lives were lost in making the tunnel under the Thames; whereas, nearly forty men were killed in building the new London Bridge.--_Note-book of 1848._ ------------------ VAST SPOT ON THE SUN.