Science Sittings

New Zealand Tablet, Volume XXXV, Issue 43, 24 October 1907, Page 35

Science Sittings

By 'Volt*

Clock and Fan. A very singular clock has been made by an ingenious- ■ Swiss workman. It consists of a dozen leaves uingedlike an ordinary fan. The number of the hour is marked ; from one to twelve, at "the end of each of these leaves. The fan timepiece starts at 6 o'clock, and expands reguhuly for twelve hours, when' it suddenly closes up and starts all over again. The half hour is indicated by the - leaf of the fan being only half extended. . Eggs in the nest. All birds have a systematic arrangement in depos-. - iting their eggs in the nest, and there are very few r . species, if any, in which some peculiarity is not to be- ; seen, if careful observation is made. Many birds so' : plainly and invariably show a tendency to a set ar- ? rarigemeht, thair their habit is generally known. r " , Natural Color of Water. „ ' *" i That the natural color of pure water is blue, instead. -* white, was long ago discovered. The green and yellow, tints are said to be due to extraneous substances. Dis- ■ solved calcium salts, though apparently giving a greenish "iint; due- to a fine, invisible suspension, have no- effect ■ on the color of the water when-' precautions are taken to prevent it, The brown or yellow color due to iron salts is not seen when calcium is present. 1 How Tinfoil is made. Tinfoil, which is extensively used for wrapping tobacco, certain food products, and other articles of commerce, is- a combination" of- lead, with -a thin coating, of tin on each side. 'It is. made in the following manner : — First, a _ tin pipe is made of a thickness proportionate .toi its -diameter ; proportion not given* This pipe is. then filled with molten lead, and rolled or beaten to the extreme thinness required. In this process the tin coating spreads simultaneously with the spreading of the lead core, and continuously ■ maintains a thin even coating of tin on each side of the centre sheet of lead, even though it may be reduced to a thickness of 0.001 inch or less. The Spider. The spider -has a tremendous appetite, and his gormandising defies all human competition. A scientist who carefully- noted a spider's consumption of food in twen-ty-four hours concluded that if the spider were built proportionately to the human scale, he would eat at . daybreak (approximately) a small 'alligator, by 7 a.m. a lamb, by 1 o'clock a sheep,^ and would finish up with" a lark pie in which there were 120 birds. Coffee as a Weather Prophet. Those who have lost all faith in the ' weather.forecasts ' are recommended to try a very simple experiment with a cup of coffee and a lump or two of "loaf -' sugar. Having dropped the lumps of sugar into the cup of coffee, carefully watch the air bubbles that rise to the-' surface. "If they'suddenly rush from th? centre to the side of the cup, be sure that it is going to rain very hard. ' If the air bubbles assemble in *tho centre, - and then pass to the - side "of the cup in a deliberate < way; you .may still b« prepared for ■ what iftie weather forecasts would call ' some showers i. - But if the bubbles refuse *to stir from the - ceittr? of the cup, you. may go forth to your labors assured' of a fine day. Manila Rope. - " \ A manila rope, properly laid and lubricated, is as "i strong, weight "for -weight, as steel;" that is, a steel s rod weighs about eight times as much as a manila rope %of the same ..-diameter, ■ and "has about eight. I titties the strength, the s'tretagjths being proportioned to the weights. When used for "> -transmission purposes, it has been found that a manila -. i. ope one inch in diameter, is equal to a double leather . Tj)elt two five-eighth" inches in width, so that three suoh^ ropes are very nearly equal to air eight-inch double belt. A two-inch rope (says ' Oassier's Ma.'gazine'i)l will transmit as much power as a ten-inch leather belt, witiile the losses from stiffness and creep are estimated' as 1 - only about one-half .with the -rope, what they are with ; the belt. ■ '■ : r x I He is indeed a busy man, who can never, find time to find fault. -