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282 the Magdalena River eight hundred miles to Dividal, seventeen hundred feet above the sea; crosses the eastern Cordilleras at an elevation of about six thousand five hundred feet to the head-waters of the Caqueta or Yapura, a branch of the Amazon, and runs down that river three hundred and seventy-five miles to the mouth of the Engarros, five hundred and fifty feet above tide-water. From the Caqueta River the route passes through Ecuador to Iquitos, Peru, crossing fourteen tributaries of the Amazon. From Iquitos it ascends the Amazon and the Ucayle five hundred miles to Napal, thence continues across the Montana, and the numerous valleys of the Amazon about six hundred miles, to Santa Cruz in Bolivia, or twenty-four hundred miles from Cartagena; while a branch will run up the Apurimac to Cuzco. This road would run for two thousand miles along the foot-hills of the Cordilleras, in which is probably the richest mining region in the world, and would greatly facilitate the opening and working of the mines. It would cross many branches of the Amazon, and thus connect with fifty thousand miles of navigable waters, at least nine thousand of which are above Iquitos, and it is claimed that the business from twenty thousand miles of navigable waters would find by this route a nearer outlet to Europe and American markets than by Pará. There is every variety of climate on the route; and the country, under a wise government, is capable of sustaining an immense population and giving abundant support to a railroad.

Purification of Sewage.—The method of purifying sewage at "Worcester, Mass., by chemical precipitation was described by Prof. L. P. Kinnicutt at the meeting of the American Association. The sewage treated contains a notably large quantity of the waste products of various manufacturing establishments, and an unusually large amount of free acids and iron salts. The Carpenter process is employed for purification. By adding lime and the crude sulphate of aluminum the suspended matter is all removed and the total organic matter is reduced over two thirds. The effluent water is clear and colorless, without odor, and with only a slight alkaline taste, and can cause no nuisance when run into a stream of not more than five times its volume. The precipitate, or sludge, is free from bad odor, and when dried contains nearly sixty per cent of iron oxide, ten per cent of carbon, thirteen per cent of nitrogen, and four per cent of phosphoric acid. Its theoretical value is about forty-five dollars per ton. If no use is found for it, it can be disposed of by burning.

Evolution of Clocks and Watches.—The beginning of modern clock-making may be dated from 1656, when Huygens attached the pendulum to the clock. This gave horology a place in the exact sciences such as it had not before held. The next important advance was the invention of the watch balance-spring, by Dr. Robert Hooke, of the Isle of Wight. lie was the author of other valuable inventions and improvements, among them the "anchor" escapement and some ingenious tools for the making of astronomical instruments. Previous to 1691 watches had only the hour-hand. Daniel Ouare, of London, added the minute-hand. Nine years later the horizontal escapement in its perfect state was made public by George Graham, F. R. S., and the device of jeweling the parts most subject to wear was introduced into England by M. Facio, of Geneva. The English Government commission on a method of finding the longitude, of which Sir Isaac Newton was a member, appointed in 1714, published the conclusion that an accurate time-keeper would furnish the best means; and an offer was made by the Government for the discovery of a method—fixed at £10,000, if by it the longitude could be defined to one degree; £15,000, if within two thirds of a degree; and £20,000, if within half a degree. John Harrison, born at Foulby, near Pontefract, in Yorkshire, in 1693, who devised the gridiron compensation pendulum, was stimulated by the offer to efforts to find a similar regulator for a watch, and devised an automatic regulator which Halley thought might prove to be of some value. He applied it to a time-keeper, which, having stood a test in a boat on the Humber, was successfully taken to Lisbon. The Board of Longitude advanced him £500. A second instrument was not satisfactory to the board; but a third won for the inventor the gold medal of the Royal Society. This instrument was sent on a long voyage to Jamaica. After