NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXIV, Issue 8020, 6 August 1887, Page 4 (Supplement)

NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

1 NEW COLOUR-PRINTING MACHINE. 1 A new colour-printing machine has boon patented by Mr. P. F. A. Godchanx, of ' Paris. There is an impression cylinder to tho machine, and according to the number , of colours to bo worked there is the same 1 number of printing cylinders required. When ' ono side only of tho paper ifl to be printed, a single impression cylinder and a single series of printing cylinders are sufficient, but 1 when both sides of the sheet aro to bo printed, • a second impression cylinder and a second eerios of printing cylinders for printing the second side of the sheet must bo employed. Each printing cylinder comprises 11 cylindrical roller, upon "which .is placed a cylindrical casing, the external diameter of which varies according to the dimensions of tho paper to be printed. At each of its extremities it carries a collar, and it is provided along its length with holicoidal grooves, in which projections on the stereotype printing plates. are caused to slide. The patentee claims a machine for printing in several colours in a single operation, and a printing cylinder composed of a core upon which movable castings of variable size can bo placed so that ,jn a single machine sheets of different sizes can be printed by simply varying tin; diameter of the printing cylinder, by means of this movable casing ; also the method of fixing the Btereoypte printing plate upon the movable casing ot the printing cylinders. TECHNICAL KDCCATIOJf. Sir Henry Konooe, M.P., has introduced a Bill to make provision in day schools by which young persons who have passed through the public elementary achooln, and others, may obtain further instruction in technical • subjects. Tho Bill empowers any school board, local authority, or managers of a public elementary school to provide day technical and commercial schools and classes for the purpoao of giving instruction in any of certain subjects. These include the several science subjects which are specified in the Directory of the Science and Art Department, and in which that department undertakes to examine. The following subjects nro also included : — The use of ordinary tools, commercial geography, bookkeeping, French, German, and other foreign languages, and freehand and machine drawin,-. The addition of other subject* may be sanctioned from time to time by the Committee of Council on Kducition or by the Science and Art Department. For tho purpose cf carrying on these schools and classes the wer of school boards, other local authorities, and school managers, is to bo in every respect the san.e as for providing ordinary elementary school?. Moreover, they are to have power to provide, or contribute- to the maintenance of, laboratories and workshops in endowed schools for tho purpose of carrying on classes or instruction under the Bill. However, all these sobools and classes are to be subject to the inspection of the ofiieera of the Committee of Education or of the .Science and Art Department. And beforo a scholar is admitted he must have passed the Sixth Standard or some equivalent examination. The Education Committee and the Science and Art Department are authorised to give|grants on such conditions as they may lay down for any of tho subjects taught in these or commercial schools or classes. For the purpose of obtaining grants, a technical school or class must be one carried on under minutes to be made by the Science and Art Department and laid on the table of the House of Commons in tho same way as the minutes that regulato tho grants of tho Education Department. HEALTH AND WELL-BEING. According to the Belgian savant, Qaetelet, a man attains his maximum weight about his fortieth year and begins to lose it toward his sixtieth year. A woman, however, does not attain her maximum weight until her fiftieth year. The weight of persona of the same ago in different classes of society also differs. In the adluent classes the average maximum weight ie 17- pounds, and is attained at 50 years of age. In tho artisan class it in 154 pounds, attained at 40. Among farm labourers it is 171 pounds, attained at 60. In the general classes it is 164 pounds, and is reached between 40 and 50 years of age. Only fifty years ago the average duration of human life- in Great Britain was thirty years ; to-day, according to statistics, it is forty-nine years. In this rifty years the population has "increased by 8,000,000. At least 2,000,000 out of these 000,00 of increase may be put down aa the fruit of improved sanitary and medical work and of victory over preventable sickness. THE POPPY. A German botanist has discovered a source of brandy and alcohol in the poppy. It appears that the pulp which covers the poppy seed contains sacchirine matter which, after due fermentation and distillation, produces a kind of brandy of an agreeable flovour. As thia pulp has been hitherto thrown away, the discovery, stis said, affords poppy-planters an opportunity of realising more profit from their crope without a very great expenditure of capital. ALTTMI.VCM. The intreeting German prooess of coating iron with aluminum is said to be having a large introduction, a Bunsen burner with a blast or inutile being employed for the operation. It ie found possible by this means to manufacture various articles of tho durable metal for daily use, the coating of aluminum giving them a silver-white lustre. Tho metal does not oxidize under normal conditions, stands ordinary heat, and takes a high polish. INVISIBLE INK FOR POSTAL CARDS. The following are, according to the Stationer and Printer, said to be good recipes for a sympathetic cost-card ink :— 1. Diluted sulphuric acid—ono part by measure of acid to seven of water. When this ink ie used the carol will at first show roughened trace 3 of the writing, but after being allowed to dry for a short time these disappear, and it la as invisible as if done with water. Of course, only a gold pan or a quill must bo used. If it i« desired to avoid the suspicion of using sympathetic ink, which might be excited by a black postal card, it may be written upon, across tho first writing, with tincture of iodine, which will entirely fado out when tho heat is applied to develop the invisible ink. 2. Uso a solution of sulphate of iron, and develop with a solution of pruseiato of potash. 3. Take a eolation of ferro'jyauido of potassium (1 to 50) ; after writing with the solution tho letters and writing are visible to the naked eye; but if a damp sponge be passed over the writing, after it is dry, then it will be absolutely invisible. The ink may bo developed in several ways. With sulphate of iron tha writing will appear blue, and with sulphate of copper dark brown ; the writing with ordinary ink, which it ia advisable not to omit, remaining unaltered. By exposure to tho fumes of muriatic acid, or by dipping into the name acid, slightly diluted, the invieible writing will bo developed of a hluieh-green colour, while the ordinary writing with nutgall ink will disappear, MISCELLANEOUS. The American Medical Journal says that in the decline of life, when exhausted nature habitually repels the restorative influence of sleep, there is nothing bo suitable to induce healthful repose as one-half to ono tablespoonful of bromide utbedtime. It may betaken for years, in the same dose, with tho same effeot and without detriment, but never except under the advice of tho family physician. To brighton and polish nickel-plating and prevent rust, apply rouge with a littlo fresh lard or lard oil on a washleather or a piece of buckskin. Rub the bright parts, using as little of tho rouge and oil as possible; wiping off with a clem rag slightly oiled. Repeat the wiping every day and the polishing as often as necessary, Artificial leather is being prepared in Germany by combining with the ekins from 5 ito ten per cent, of sinews. Pieces of leathor are washed, cut, boiled in alkaline lye, torn, neutralised with hydrochloric acid and washed once more to remove all traces, of acid. To this are added sinews, which aro treated similarly and steamed in an acid bath until they are somewhat like glue. The materials aro then mixed, pressed into sheets, moistened on both sides with a concentrated solution of alum, and the upper surface receives a thin coat of caoutchouc in solution with carbon bisulphide. To cover a sphere with tinfoil, tho foil is cut into gores so as to slightly overlap. The very thiokest parts aro used. Each gore is rubbed with the thumb-nail, or aide of a test tube, until it lies quite smooth. This is if the plasticity of the tin permits. To make a bond in glass tubing without flattening, two inches of the tubes should be heated in an equal temperature. This may be done by holding the glass widthwise in the flat flame of an ordinary gasburner. There are fifty-one active volcanoes'; in Japan. This accounts for the multitude of hoc springs in that country.