NOTES AND QUERIES.

Otago Witness, Issue 3316, 3 October 1917, Page 39

NOTES AND QUERIES.

Qoastiom Cor reply In coming Issue to !» received not later than SATURDAY niglit. Questions will NOT b* replied to througi. ih» poet.

Otautau.—The sample of material you sent for identification was submitted to Professor Park, who has reported that it is iron pyrites, the yellow brassy-coloured disulphide of iron. This ore.of iron is used for the manufacture of sulphuric acid. It occurs as nodules in clayey rocks, as grains and crystals disseminated in coal, slate, schist, sandstone, in many altered igneous rocks, and in taosi metalliferous lodes associated with gold or ores of copper, zinc, lead, silver, mercury, and nickel. It is perhaps the most widely spread of all the ores of iron; but it has no commercial value except it occurs in massive lodes, or as an associate of some' valuable metal, from which it is separated as a marketable by-product. Curious. —Presumably your question refers to the Royal Garrison Artillery in England, the cadets of which, like the cadets of any other branch of the army, do not go into the firing line. Being cadets, they are under military age. New Chum asks:—"(l) Can a recruit holding a C2 medical certificate apply for a position in any of the following services:—(a) The Army Service Corps, (b) the Transport Divisions, . (c) a Home Service Abroad ? (2) And if so, to whom would he need to apply ? (3) What does ' C2 D special' mean?" (1 and 2) A C2 man,is classed as fit for home service only, and it would be of no use his applying for a position in the Army Service Corps or the Transport Division. By home service abroad you mean, of course, out of New Zealand. That, too, would be barred to a C2 man in New Zealand, who would be retained for home service in New Zealand. (3) There is no such classification as C2 D special. You probably mean Class D, those absolutely unfit—such a case is that of a man mentally deficient or one suffering from a contagious disease. A Parent-asks:—"(l) Could a girl who has passed all the standards at a public school (without failing in any class), and who obtained a proficiency certificate, hold a position as governess? (2) Could children, living close to a public school, who are very backward in the lower classes, be kept and taught at home by a governess? (3) Must children, being taught at home by a governess, be examined by a head master of a public school or an inspector?" (1) Yes. (2) Yes, provided the parent obtained certificates of exemption for them as prescribed by section 60 of the Education Act. The instruction would require to be as regular and as efficient as in a public school. '(3) No. Newton has in her possession half a dozen New Zealand 2Ad stamps, issued in 1899, with the mis-spelt name "Wakitipu printed thereon, and wishes to know the present-day value. Too many of these "error" stamps were printed to make them really valuable. They are on sale, unused, in Dondon at 3s 6d per dozen. Many people have been using them for postage of late. Inquires asks how to set rid of silver-fish. —■ —Various insecticides (Pyrethrum powders), sprinkled where these insects are most numerous, form a reliable remedy. Powdered borax or benzine is also good. The former should be sprinkled in their haunts and the latter syringed into any crevices. Another method is to soak blotting paper in a mixture of equal parts of oil of camphor and spirits of turpentine, and Jay it near their haunts. Saline. —The production of salt from sea water is thus described: A large piece of land, barely above high-water mark, is levelled, and, if necessary, puddled with clay". In tidal seas a storage reservoir is constructed alongside, similarly rendered impervious, in which the water is allowed to settle and concentrate to a certain extent. In non-tidal seas this storage basin is not required. The prepared land is partitioned off into large basms, which get smaller and more shallow in proportion as they are intended to receive the water as it becomes more and more concentrated, just sufficient fall being allowed from one »et of basins to the other to cause the water to flow slowly through them. The

flow is often assisted by pumping. The sea salt thus made is collected into small heaps on the paths, around the basins, or the floors of the basins themselves, and here it undergoes a first partial purification, the more deliquescent salts (especially the magnesium chloride) being allowed to drain away. Ftoui these heaps it is collected into larger ones, where it drains further and becomes more purified. The

salt is collected from the surface by means of a wooden scraper.

Violin.—The fact of your violin carrying the label is presumptive evidence that it may be a genuine Strad, but it is not conclusive proof. Only an expert could decide the point definitely. Unscrupulous makers have not hesitated about attempting to pass off their makes as genuine old masters; and thus eomething mere than

a label is required as proof of genuineness. Fabmer, Clinton.—Mr H. M y Davey, consulting engineer, replies:—"l am asking the editor to post to you what you require in your first question, and you should be able to find the quantity with it; but, as it says, if you cannot work out the table sent with the information, all you need do is to give me the length of the slot and depth over it. To find the fall, get a board like a flooring board, about 6 in.by lin thick or so, as lone: and as straight as you possibly can; also a good spirit level and a rule. Now, say tho, board is 15ft long: you start at the highest of the ground to be measured, and place the one end of the long board on the ground at the level of where the bottom of the race for the water would be, and place the level (which you had better tie on to the long length; and if you got 2ft 6in measurefrom the ground to the underside of tho board. This gives you the level of the first length, which we are presuming is 15ft, a.nd the length as well. Now, suppose the measurement were 2ft Gin. Then you move the board its whole length towards the place you are measuring to, placing the end that was. at the race level at the place you measured the height, and so on, getting the distance from the ground to the underside of the long straight-edge each time. Now, supposing you moved tho boa.Td forward its full'length 20 times, you get 15 x 20, equal to 3Ooft, as the total length; and if you got 3ft Gin measurement each time, you add these together; 20 times 2ft Gin is 50ft, which would then be thejjotal fall. Anyone that is a builder or a house carpenter could show you how_ to level if you cannot understand the above description."