NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXXI, Issue 9581, 4 August 1894, Page 4 (Supplement)

NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

; • TWO MILES THROUGH GKANITK. ... The tunnel which carries the - Coloradc Midland Railway through the Rocky Maun' tains at Hagerinan Pass, Col., has just been completed. The tunnel is closs upon iwc miles long, and it is < bored, through' solid grey granite. Its completion involved three years and twenty days' work, ; each day comprising 20 working hours. The tunnel is 10,890 ft above the sea level. STAR CHANGES. For the most part the stars' maintain their places and brightness apparently unchangedthe heavens of to-day are substantially the same as those of Job and Homer. The comparison of a. modern star catalogue with that of Hipparchus as; preserved by Ptolemy shows that, with few and generally slight exceptions, the principal stars still hold the same relative positions, and the same rank in brightness which they did 2000 years ago. ? And yet we know that all the time they have been swiftly moving in all directions at rates sometimes exceeding 100 miles a second some appioachiug us and some " receding. Then, too, they have all been growing old together, some advancing from stellar ; infancy toward adult vigour, and some descending toward extinction. The apparent permanence is apparent —due simply to the fact that the scale of human life and our terrestrial surroundings is practically infinitesimal as compared with that of the stellar universe. Even the nearest star is so remote that if it were rushing, directly toward us with the speed of 100 miles. a second it would gain in brightness only about two and a-balf per cent, in a century, an amount barely observable by our best photometers. As to changes due merely to advancing age, a century bears only some such ratio to the lifetime .of a star as.a single minute to that of an aged man. ■ COMPRESSED AIR. ' '. _ An air-pump for cleaning purposes is in use in America. A hosepipe charged? with air under 50lb pressure to the square inch is turned upon the article or room to be cleaned. It is used in precisely the same way as the water and hose for washing purposes. It is far more effective in its results than brooms, beaters, or brushes, as it searches out and penetrates every crevice and cleft in woodwork. This device is at present applied to cleaning . " cars" in America, but so perfect is its work that.it is only a question of time when it will come into use tor other purposes. Hotels and large buildings might he swept out and dusted in an incredibly short space of time. Carefully managed, this air pressure would rid the room of every particle of dust, clean furniture, carpets, and the heavier articles of brie a-brac and ornaments, It would do the work of a dozin people. It is now in order for some home missionary to invent some simple device that will work an airpump and current for household use. Its introduction would revolutionise housekeeping and solve the heretofore hopeless problem of clean rooms, and will preserve furniture covers and carpets. FATALITIES DUE TO ELECTRIC SHOCKS. _ After studying and classifying fatalities due to electric shosks, including the executions which have taken place in New York, MM. Biraud and Lacassagne, of Lyons, announce that electricity causes death in two ways—first, by producing mechanical lesions of the blood vessels and nervous system ; second, by stopping the respiration and action of the heart. Deaths belonging to the former class are caused by lightning and static discharges from powerful batteries ; but those of the second class are met with in shocks from- high-tension currents used industrially. A French paper, in commenting upon the investigation, takes up the subject at this point as follows —" These two classes of death are distinguished also in practice by a most important fact. While disruptive discharghes of the first class cause death absolutely, the electric action in the second case most frequently puts the victims in a state of apparent death, and they can be revived by resorting to artifical respiration immediately after the accident. Thus, in accordance with a principle stated by d'Arsonval, a person who had received au electric shock should be treated exactly as | one who has been drowned. .None of our skilful physicians have, it is said, succeeded in killing with certainty a luckless rabbit, even by employing a current of 2500 volts and 20 amperes. When the experimenter has believed he has succeeded, it has still artificial respiration. Yet it is questionable if machines used for electrocution in America give 1500 volte. D'Arsonval some time ago challenged the American doctors to try artificial respiration on the patients immediately after electrocution." TIIE ELECTRIC UTILISATION" OF NIAGARA.

The necessity for having manufacturing establishments located where the water wheels are has greately limited the use of water-power. Now that electric energy can be transmitted to greater d istances on wires, one may have his source of power with a dynamo where the water-power chances to be, and his factory with its motor where ib is economically best to pub it, and these places may be many miles apart, and many rivers may be made serviceable which have hitherto been but a waste of power. One of the largest of these is the Niagara River and falls, where about 18,000,000 cubic feet of water flows per minute through a descent of more than 300 feet, including both falls and rapids. This represents something like 10,000,000 horsepower. For the utilisation of a portion of this a company has constructed a tunnel about a mile and a-half long running under the town of Niagara, from the river above the falls to a point just beyond the footbridge below the tails and a few feet from the. surface of the river, giving nearly 200 feet for a head of water. The capacity of this plant is 100,000 horse-power, and there are to be many turbines, some of them 5000 horse-power, for driving 5000 horse-power alternating dynamos intended to maintain a current at '2000 volts Manufacturing establishments in the immediate vicinity will probably have wires connected directly to the dynamos, bub factories at a distance of ten or more miles will have the voltage raised by transformers to 10,000 volts or more, and again transformed .to lower voltage where the power is to be utilised. This process is to save in cost of conductors, for a given amount of electrical energy of high voltage requires a smaller wiro than if voltage is low. A number ten copper wire, which is about an eighth of an inch in diameter, which will conduct, say, 30 horse-' power at 1000 volts, will conduct 100' norse-power at 4000 volts. It is expected, says a writer in the • Cosmopolitan, that most of this power will be used for motor work rather than in lighting, and Niagara companies have been organised in several cities and towns about, some of them at the distance of 100 miles or more, with the probability that ultimately some of the enorgy may reach even New York city. - It seems likely thab the region about Niagara will soon become a great industrial centre, where all sorts of mechanical enterprises will be grouped, because power can be had cheaper than elsewhere. There are many questions concerning the economical distribution of electrical energy that will be settled by this Niagara plant, and engineers are watching the developments with great interest. After these are settled, by experience, water-power in places now inaccessible for manufacturing purposes will suddenly become valuable properties for electrical power stations. No one need feel apprehensive thab Niagara falls will be seriously affected by this seemingly large draughb upon its water supply. In reality it represents bub about one-fortieth of the bulk of the water of the river, and several such power plants might be established there without diminishing the flow appreciably. .TtJPITER'fI SATELLITES. Some observations by Professor Barnard on the satellites of Jupiter are in direct contradiction of current beliefs. For example, he finds thab all the Jovian satellites are spherical, whereas Schaeberlo and Campbell announced less than three years ago that Satellite I. y/m ellipsoidal, with its longest axis directed towards the centre of the planet. Nor do Mr. Barnard's data confirm the conclusion that the periods of rotation and revolution of the first satellite are equal. Among other points, Professor Barnard criticises with American plainness of language the belief among astronomers that the satellites can bo seen through the planets's limb during occultations. After studying them for fifteen years he has nob been able to notice anything confirmatory of this. 44 In my mind," he tells us in his paper, " this has been due to poor seeing, a poor telescope, or an excited observer"—a fine comprehensive style of stricture which like the blasphemy of Huckleberry Finn's father, leaves nobody outside its sweep.