SCIENCE AND INVENTIONS.

New Zealand Herald, Volume XLIX, Issue 15169, 7 December 1912, Page 4 (Supplement)

SCIENCE AND INVENTIONS.

NEW SILVER PLATING POWDER. Silver plating can be accomplished, according to a new German process* by dissolving freshly '• precipitated chloride of silver in a solution ol nyposulphite ot soda (1.1 parts to. 10 parts of. water), adding 0 180 part of sal ammoniac to this solution and' stirring 111 GOO , parts of finewashed chalk. This - mixture is rubbed on the article to be silver-plated until it dries, and a bright deposit of pure silver will be obtained.? ~ ' ' . . .

LONGEST TUNNEL .. IN\ AMERICA^

The next big rail way. project of.the/HarV riman system, states the 'New York Herald,'is a 30,000 ft tunnel'in the Sierra Nevada Mountains.. This is part of the programme of track improvement' under way 'between . San Francisco and Omaha. This tunnel will be .the longest ' on the continent. •' Mr.'-Lbvett intimated the cost, would be in-excess, of £2,000.000. .Trains propelled by electric power will have to be used" in the bore. The objecE :of the tunnel is to cut . out' about 1,000,000 feet 'of track on the present mountain grades. • THE ELECTRIC OVEN. - One. great advantage that the electric oven has oyer other ovens is; that, food in cooking loses little of-its weight. In. an address before. the Wisconsin Electric Association, Mr. J. D. A. Cross, of Chicago, said- that careful experiments have shown that,when meat is cooked -the ordinary coal or gas range it loses from a. quarter to a third of, its weight, whereas - it loses only from a tenth to a seventh when it is cooked by electricity. Tho saving by the electric process.over,the results of- gas and coal !processes amounts;to a pound and ahalf in a 91b leg of lamb: • HEARING LIGHT. A new instrument, "The■; Optophone," is stated to have been invented, which makes light audible. The invention is based on selenium, possessirg property .'■of", changing its resistance when illuminated. A sensitive indication can be made to move by merely holding a lighted match over a selenium cell, to which is attached an electric battery. This move-' ment is in tho optophone attached to a telephone arrangement -and so made audible. It is claimed by the inventor that-though the blind cannot actually see, yet by this means they will be able to locate light by th© sound. IMITATION COAL. Professor Dr. Bergius, of Hanover, claims to have succeeded in producing artificial coal. The process consists in the application of heat, and pressure to cellulose, or to ordinary turf. In Nature the coal-forming process took eight million years to complete, whereas Dr. Bergius's process takes only about eight hours. He places, his cellulose in a specially constructed apparatus which permits of the union of pressure with high temperature." The cellulose is heated together with water at a pressure of 100 atmospheres, and tho product cannot, it is said, be distinguished from ordinary hard coal. LONDON'S "LEANING TOWER." The steeplo of Bow Church, into the rectorv of which Canon Masterman has just been inducted, is the nearest London analogue to the leaning Tower of Pisa. It is considerably out of perpendicular, as can easily bo perceived from Cheapside, but not to a dangerous degree, and no further settlement has been noticed of recent years. The steeple* sways when the famous bells are rung, but this is considered a proof of elasticity, and so of strength. The copper-gilt dragon, nearly 9ft long, which forms the weathercock, was supposed when first erected to stand for the High Churchmanship of the day. SEAWEED AS FOOD. Dainty dishes from seaweed and other plants of the deep are promised. It is claimed by Miss Josephine E. Tilden, who occupies the Chair of Botany in the Minnesota University, that. once this course of food supply is tapped the weekly problem of'the poorer classes caused by the high cost of living will be solved in some measure. The only cost involved is, the gathering and drying, and the time is not far distant when this fine soup ingredient will be used by the masses of the American people, at any rate. Tho properties contained in beef and all classes of vegetables used for food are also found in seaweeds.

THE FATE OF A FAMOUS ROCK. The famous balanced rock which has been one of the natural curiosities of the province of Buenos Ayres, Argentina, since time immemorial, lost its balance in tho early part of this year, rolled down the steep incline of the mountain, and was crushed at its base. The rock measured 16ft. in diameter, and was about 13ft high, weighing about 000 tons. It was so nicely balanced, says Popular Mechanics, that it swayed in the wind. Its loss of equilibrium is variously ascribed to natural causes, and to the tourists' custom of throwing empty bottles between the rock and its supporting cliff, to see them crushed by the rock's swaying. This bottle-crushing procedure is claimed to have caused abrasion of both the rock and cliff.

WASTE IN COAL MINES. Dr. Joseph A. Holmes, director of the United States Bureau of Mines, in a bulletin just issued, says that during the lastyear one half as much coal has been wasted or rendered unfit for us» as has been mined and put on the market. In view of this he thinks it is high time that more vigorous efforts should bo made to reduce this enormous waste, not only in coal, but in minerals generally. Tfais is the purpose of investigations now under way by the experts of the bureau. Dr. Holmes says: During the last year, in producing 500,000,000 tons of coal, we wasted or left underground in such condition that it probably will not be recovered in the future, 250,000,000 tons of coal we turned loose into the atmosphere a quantity of natural gas larger than the total output of artificial gas during the same period in all the towns and cities of the United States, and we also wasted, or lost in the mining, preparation, and treatment of other important, metalliferous and non-metalliferous minerals from 10 to 15 per cent, of the year's production of such minerals.

WHY NOT FEET PER SECOND It is a singular .testimonial to tnc persistence of impressions and the natural conservatism of mankind that we continue to use familiar expressions long after they have lost their original correctness of application. Thus wo say "miles per hour" in estimating rates of speed, even in cases where only very short distances are covered. This practice has become a habit, and not a very creditable one at that. Much better would be f the expression " feet per second," and this phrase would be equally understandable and far more explicit. " Miles per hour" is easily reduced to " feet per second" by a simple formula (the multiplying of the rate of speed in miles per hour by 1.467). Conversely, the rate of ■ speed in feet per second is converted to miles per hour by multiplying the " feet per second" figures by 0.682. Approximately, " feet per second" is one and a-half times "miles per hour," and similarly "miles per hour" is about two-thirds "feet per second." The following table will be found useful for quick comparisons —

Miles Feet Feet Miles per hour, per second, per second, per hour. 1 1.47 1 .68 2 2.93 2 1.36 3 4.40 3 2.04 4 5.87 4 2.73 5 7.33 5 • 3.41 6 8.80 6 4.99 7 10.27 7 4.77 8 11.73 8 '5.45 9 13.20 9 6.14 10 14.67 10 6.82 20 29.33 20 13.64 30 44.00 30 • 20.45 40 58.67 40 27.27 50 73.33 50 34.09 60 88.00 60 40.91 70 103.67 70 47.73 80 117.33 80 54.54 90 132.00 90 61.36 100 145.67 100 68.18