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THE POPULAR SCIENCE MONTHLY. 



the Magdalena River eight hundred miles to 

 Dividal, seventeen hundred feet above tlie 

 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, cross- 

 ing 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 nu- 

 merous 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 Para. 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 establish- 

 ments, 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 sus- 

 pended 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 impor- 

 tant advance was the invention of the watch 

 balance-spring, by Dr. Robert Hooke, of the 

 Isle of Wight. lie was the author of oth- 

 er valuable inventions and improvements, 

 among them the " anchor " escapement and 

 some ingenious tools for the making of as- 

 tronomical 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 de- 

 gree. John Harrison, born at Foulby, near 

 Pontefract, in Yorkshire, in 1693, who de- 

 vised 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 ap- 

 plied 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 



