SCIENCE NOTES.

New Zealand Herald, Volume LXIII, Issue 19418, 28 August 1926, Page 4 (Supplement)

SCIENCE NOTES.

SCIENCE EN INDUSTRY. MATERIAL AND UNITS. STUDY OF THE CRYSTAL. In opening the annual meeting of the Institute of Physics,, a few weeks ago, Sir William Bragg laid emphasis on the bonds between pure science and its applications in industry. In preparing his Royal Institution Christmas lectures last winter on " Old Crafts and New Knowledge," he said he had become impressed with the dependence of an industry upon its understanding of the material with which it dealt. That material could be resolved into units. In metal-work the unit was the crystal, said the lecturer, though intimately the atom; since the properties of the orystal immediately expressed those of the atom, the crystal might be the object of investigation. Sorby's introduction of the microscope study of metals sixty years ago, had been a move in this direction; X-ray studies had carried the matter farther, and had shown that plastic deformation took place by alternate slippings over definite planes in definite directions in which the crystals tended to lie. Crystals were generally more or less oriented in metals, or becamn so by work done upon them. If we could find the connection between properties, form and orientation, we should have made a new advance in metallurgy. Sir William then passed to the unit of the textile craft, the fibre, which consisted of an elastic framework, certainly of crystalline structure, with a preferential direction as in all forms of growth, and a viscous material; study of tins would bring strength and new development to the textile industry. It was similar with the dye industry and the oldest of all crafts, that of the.potter. There the old rule of thumb still held, because nobody could say exactly what was clay, or explain plasticity, or give the reason that clays of similar composition differed so widely in this property. v X-ray examination had shown, the speaker continued, that the fundamental particle of a china clay was a crystal,

and that the crystalline structure changed at a certain temperature; these problems, however, were extraordinarily complex. Although tradition and secrecy still prevailed in the pottery industry, research associations had made important contributions to pure science. SUBSTITUTE FOR GOOAINE. A now synthetic substitute for cocaine, which can be used as a local anaesthetic, has been discovered In Germany. It Is named "totokain" and is prepared from some of the intermediate products in the manufacture of artificial rubber. WHEN WE " SEE STARS." A blow on the head makes a person see stars by jarring an octave nerve and so stimulating it. The brain is in the habit of receiving from the octave nerve stimuli which, it recognises as light. Accordingly, the stimulus caused by the jarring of the nerve also impresses the brain as bung a light stimulus, and the person thinks he sees a flashing light which takes the form of moving stars. WIRELESS ENERGY FOR PLANTS. An amateur gardener in England has found a way of using wireless energy to stimulate his plants. He discovered that his cucumbers and tomatoes were drawing energy fiom his aerial and began experiments which have lfd to the claim that he has increased fertilisation in his garden by between 20 to 30 per cent. The appa ratus used consists of a spiral wire, with insulators attached, which can be stretched to a required, length.

THE USE OF HOT BEDS. SEEDLINGS AND CUTTINGS. A properly-made and managed hot bed composed of stable manure, leaf rubbish, and other fermenting materials, is extremely useful at this season of the year in supplying a moist, genial heat tor the propagation of the different varieties of soft-wooded plants, the raising of seeds, especially cucumbers and melons, and also for striking cuttings

that are wanted in quantities for bed-ding-out purposes, notably alternantheras, iresines, and others that strike root ever sj much quicker and more surely than under the ordinary process. The moist heat generated from the fermenting materials keeps the cuttings free from red spider and thrips that some plants are liable to under cool treatment. PREPARING THE BED. Fresh stable manure should be procured and well mixed with a quantity of leaves. Turn the whole over every other day for about a week, well water any portions that are dry. It will then be ready for the construction of the hot bed. Build the heap according to size and shape if the frame to be used, allowing an extra width of about 2ft. all round outside the fiame. WelJ tread the mateiial to secure a uniform heat throughout, and raise .& to a height of from 3ft. to 4ft. above thi- surlace upon which it is placed. Place the frame with the glass lights upon it and allow all rank steam to pass off before any cuttings or plants are placed inside the frame Stable litter by itself heats much too violently and does not last long, hence the desirability of mixing a good proportion of leaves with the manurs. With the addition of the leaves the heating properties are slower but more lasting and better for the plants. AFTER-MANAGEMENT. Place a layer over the surface of sawdust or coconut fibre, which is better, if obtainable, in which to partly plunge the roots, or place the seed boxes or cutting trays upon. Allow a little ventilation by placing a tilt at -the tops of the glass lights by night and day for a short time after the bed has been made

up. Properly prepared, the heat will be retained,, for a considerable time, and when it becomes too cold the addition of a little fresh material mixed with the old will provide a genial heat for a further period. SOWING SEEDS UNDER GLASS. Whether seed pans or pots or shallow trays are used they should always be clean, dry, and well drained either with broken up crocks, or for the hardier kinds, a layer of' stable manure on the bottom of the seed trays, which are invariably used for the sowing of most varieties of flower seeds.

THE SOIL FOB SEEDS. Seeds of any description require a lighter soil to germing them in than the plants will grow in when established. The amount of soil required to cover the seeds is, as a rule, about equal to their own depth. Many of the longer seeds require to be covered considerably deeper. With very small seeds such as begonias, a light dusting of fine earth sifted through a fine sieve is ample. If covered too deeply they perish before reaching the surface. These should be covered with a pane of glass and a little moss placed on' the glass to shade and keep the soil moist. As soon as the seedling appears above the surface, remove the shade and wipe the glass every morning until I,hey are large enough to dispense with glass. TREATMENT 0? SOIL, The soil, especially for fine seeds, should be well watered and the moisture allowed to soak through before sowing the seeds, otherwise the watering will wash them out of the soil or into patches. Flower seeds should have the seed trays covered with a sheet of newspaper until they germinate and appear above the soil,when the covering must be removed to prevent the seedlings drawing and damping off. The covering prevents the surface soil from becoming too dry, retains a uniform moisture and does away with the necessity of frequent waterings, which are detrimental. Always avoid sowing seeds too thickly. Amateurs, and, indeed, professionals, too, often err in this respect. The seedlings come up so crowded that they are difficult to prick off.

; PLANTING CITRUS FRUITS. PREPARATION OF SOIL. The planting of lemon and other citrus fruits can now be carried on' with comparative safety. Situations and localities subject to severe frosts, especially during the present and succeeding month, are preferable for earlier planting, for apart from there being little risk of injury by frosts, there -is at this time more warmth in the soil, so that root action is more rapid, and the plants soon become firmly established. This, however, is not always followed by immediate top growth, which is often a source of anxiety to the planter, for it frequently happens that even when planted under the most favourable conditions, and healthy root action is tisking place, little or no young growth is ma <*o until late summer qr early autumn, when they break into healthy, vigorous growth. It is for this reason that wnen planted in districts subject to severe frosts some protection should bo given during the winter, or until the plants are sufficiently advanced and hardened to stand _ tho climatio conditions. Refora planting lemons, oranges, or, in fact, any of the citrus family, it is important to have the soil thoroughly prepared beforehand, and if the subsoil is at all of a stiff nature, thorough drainage must he provided for; for while a reasonable ' amount of moisture is essential to ensure healthy growth, there are few plants that succumb more quickly through an excess of it. The soil best suited for citrus ffuits is a deep, rich loarn, or soils in which sand or other gritty matter is freely distributed. In such soils the land can be deeply' worked, and there will be free outlet for surplus moisture, without having to resort to artificial draining. But in soils of a stiff nature, drainage must in every case be provided for, while the holes should be filled with the best soil obtainable. Citrus trees luxuriate in well-deeayid, vegetable matter, and when this is obtainaßle, should be well incorporated in the soil before planting. In planting the greatest care should be taken not to place the roots too deep in the soil; in fact, it is always advisable to have tho plants slightly raised above the surrounding surface, and in no case to cover with soil the part whore the buds or grafts have been inserted. Deep planting is the cause of many failures, so that too much attention cannot be given to this matter. In almost every instance, experienced raisers of citrus fruits insert the buds or grafts sufficiently far from tho ground to allow of the roots being properly covered without the soil being in contact with the bud or graft. It is when tho plants are buried beyond this point that decay, or what is usually called collar rot, sets in. All citrus fruits thrive best when planted in soils that have been well worked, and under good cultivation, as the plants are are naturally surface rooting, and when growing freely require ample space for the roots to extend. As soon as the trees are planted they should be securely ■staked to prevent them being swayed about with tho wind. Tho fact of their being shallow, planted upon slightly raised mounds, renders them more liable to injury by wind than more deeply planted trees. The subsequent treatment will consist in keeping down weeds by light hoeing, and by mulching with manure or other suitable material.