SCIENCE and INVENTIONS.

New Zealand Herald, Volume LIV, Issue 16669, 13 October 1917, Page 3 (Supplement)

SCIENCE and INVENTIONS.

/ • TROPICAL BAINS. V Tropical rains .' are ;of relatively "short duration, by ; reason of the small number of cyclonic storms/in the tropics, and this is fairly uniform.throughout .thej year.;'-: The '. heaviest -;general/rainfalls in Porto-Rico are" associated /with; . West Indian hurricanes. : The , historic" hurricane of/August 8, 1899, precipitated; rainfall equivalent to 1113 tons'per/acre.'-. •/

PENCILS MADE IN. CANADA. . The 'war has made Canada realise the possibilities which- f were only awaiting the opportunity.? to develop in many ways. One striking instance is the fact that before the .outbreak of hostilities the Dominion bought all' the lead pencils it required from Austria. Now. Canada is not only making sufficient to supply her own needs, but ■■ is selling large. quantities to the other parte of the world. ■ .'.."-:' ;. ... AERONAUTICAL INSTRUMENTS. _. The development of aviation has brought into' existence several new lines of industrial activity, not the 'least of which is the production' ;of instruments for aerial navigation, in which-several instruments Used' in - navigation ;at sea'; play their : part when adapted to the newer use, but in addition ; there are many'other devices in existence at the present time and a great demand exists for others. All the 'devices used'in > the automobile, on the dashboard arid under the bonnet are to be found in the.; up-to-minute aeroplane, 'arid 'many

others too. .; There is the altmeter, which is a barometer adapted to aviation; the inclinometer, the drift ' meter, the distance indicator, .the 1 barograph; the angle (of _ attack indicator, ; the stallometer, tho clinometer, and others, all of which add to the aeronautic industry 1 arid to tho maze, of details aviator must master.., ;, / :

: COLOURING COPPER. / /-_; «. Copper lends /readily to colouring, processes, and /; may .. be worked to all shades imaginable, excepting, the lighter shades, which are lost on a copper surface, as that metal cannot be given a tint, lighter than its natural colour. Copper can be carried through the entire range, of shades/ from a very light copper colour to the darkest brown, or even hlack/ bymerely oxidising the surf ace of the metal. Make a paste of iron oxide and graphite, with alcohol wood or with plain water (the alcohol dries out quicker and allows the process to be hastened), then heat the article in an oven or over a gas flame. The colour obtained will depend on the' amount of iron oxide mixed with the graphite, and the length of time' the heat was maintained. /The mere iron oxide in the coating the darker the shade given to the copper. The remains of the coating should be removed by a'brush or cloth moistened with alcohol, and when the surface ' has become quite clean ..protect •" the -colour by applying yarnish, lacquer, or- pure wax, which may be. laid on with a brush while the copper is heated. Some brown colours are obtained by using a mixture, as above, of verdigriß, ,sal ammoniac, ;• and vinegar, using.two to three times us much of the verdigris and sal ammoniac as/ of the vinegar. The heat treatment is the, same ;as in the preceding process, and the colour obtained ; can 'be made very _ much ; darker by , adding some blue vitriol to the solution/ A rod-brown , may be _ given by using a vinegar paste containing equal parts of. verdigris and < cinnabar, together with two and ' a-half times as much each, of sal ammoniac and alum. The heat treatment is/ the • same /for /the coatings. A wide range of h colours,' comprising shades from a blue-black/ to blue-grey, may given to copper by dipping in a hot liver: of sulphur" , solution afcd then washing/::thoroughly,;' , re-dipping ~= or scratch-brushing ; and : again ' dipping . and washing, t according to- the tint desired. This > must be learned by * experience. Much information can be gained by taking some of the., solution' and some small pieces of copper and -einierimentuig/-/v /