NOTES AND QUERIES.

Otago Witness, Issue 2622, 15 June 1904, Page 47

NOTES AND QUERIES.

Queslions for reply in oming istue to be received not later than MONDAY night. \

Draughtsman.— Mr H. M. Davey, consulting engineer, Moray place, kindly replies: — You do not appear to make it quite clear as to •whether you intend to go in for the land or marine branch of engineering, and it is cbvious that the courses somewhat differ. However, from the most reliable source, you may be certain that for the first and second classes of stationary engineering ''Rochfre" (ss) or "Wannan's" (sr), or for marine engineering "Reid's Handbook" (17s), aie among the best books for your purpose. Almost any mechanical pocket-book or hand-book gives the sizes of bolts and nuts — "Spons's" (2s), "Mole3worth's" (6s 4d), and Messrs John Chambers and Son (of Auckland) have a very handy book (about lOd posted). Trie prices given above include postage. Mr Braithwaite, of Princes street, Dunediu, keeps all these, but you might get some m your own city. For drawing, you really need practical work at it in an office where designing is done. It is of but little real advantage to merely copy out drawings frornr prints, though this would, perhaps, be of a little service. Constant Eeadeb, Lee Stream.— -Mr Davey replies: — Unless you can manage in some way to get more fall (at least two or three times the amount you have) a Pelton wheel seems out of the question.- They never seem to have been used unless at twice your fall, and then only one maker appears to contemplate as small a fall as that. A really gcod low-pressure turbine should give you 2£ h.-p. barely, an overshot wheel 2 h.-p. barely, and a high breast wheel 1J h.-p. Different makes of turbines trs.vel at different speeds, but one for the conditions you name might revolve at, say, 500 per minute if a quick speed one. (2) This question is answered m the first answer. (3) The size of pipe (if a pipe is used) would depend on the make of turbine, but if a wheel there would be no pipe needed. (4) Is answoied m the first reply. (5) This is probably the best method of conveying power, if large pulleys are used and the distance from pulley to pulley is considerable. (6) Molesworth says that this is an economical method of conveying power for any distance not exceeding thice miles. (7) Your pulleys should not ba less than 4ft in diameter, and they would run at about 100 revolutions per minute. The rope should be the best quality flexible steel wire rope, of a diameter of three-eighths of an inch (called an l^in rope). This will transmit about 4 h.-p., but remember that this is at •this speed, for at diffeient speeds ropes of any given diameter or size transmit different powers, and this is about the speed you say you want. See also answer to "Circular Saw" in this issue. Circular- Saw, Oamaru. — Mr Davey replies: — Your saw should run at such a speed that the teeth travel at about from 6000 ft to 7000 ft per minute, so that a saw lft in diameter would run at, say, about 2000 per aninute, or a little over, and an 18in one about, say, 1400 revolutions per minute, or a little less. (2) Seeing that you state at the bottom, of your letter the small distance 'between the shaft and saw, it is more than probable that a good belt would be better than a wire rope, and also it would be easier shifted from the fast to the loose pulley and vice-versa. 0*) Not knowing whether you are going to iise a 12in or an 18in saw, and seeing that these should run at different j speeds, and seeing also that pulleys are ] generally sold with a saw of suitable size, for that saw this question cannot well be answered, but you will get a good idea from the reply to ihe first question. Anyhow, have your, pulleys on the large size, if yovi can, there being nothing but a trifle m first cost to be gained in having small pulleys," and they are very hard on the belt, seeing v that they need a tighter belt, and the belt has to bend so much quicker io s;oing round small pulleys. (4) Probably the saw pulleys are "bought with the saw. You will either then get the speed with it, or above, and that would give you the other pulley's diameter; but if you need another reply, write again. See also reply to "Constant Reader," the latter part of same, in this issue. E. F. P. — We have submitted your questions to Professor Park, of the School of Minea, -who kindly replies : — Eight samples for identification: No. I—Flinty1 — Flinty quartz with specks of iron pyrites, contained no gold; No. 2 — Ferruginous sandstone ; No. 3—Sandstone with cavities lined with small quartz crystals; No. 4 — Flinty quartz, contained no gold; No. s—Vein5 — Vein of grey pulverulent quartz, contained no gold; No. 6 — Sa-mple of granite pebble ; No. 7 — Fragment of granite;- No. B—Fragment8 — Fragment of granite. The granites were probably derived fromi one cf the granitic conglomerate beds interb'edded ■with the juro-triassic rocks which occupy ■the greater part of Southland. Subscriber, Ida Valley.— The silver-grey rabbit is a uniform-coloured variety, the fur of which is a rich chinchilla grey, varying in depth of colour in the different strains. They breed true to colour in the open. Eealih.— (l) There will be no duty to pay on ihe books. (2) Whole meal is obtainable at any of the chief city grocers'. It would be as "well for you not to place too u^ucll ie-

lianoe on all you read as to the virtues of , whole meal bread, however. It Is an agree- i able change now ami again, but at present there is a revulsion in some quarters in ' favour of the maligned white bread. J. N. M., Kirnberley, Cape Colony.— "Dmornis" thanks you heartily for the fine specimen of large praying mantis, or " Hottentot god, ' j which arrived in good condition. Pleased to hear that you receive the Witness regulaily, and find it "always interesting." Colonial Boy caai get Mr Weinman's address by writing to A. J. Park and Co., patent attorneys, Box 572, Sydney Also full particulars of suction dredge. There aj.3 five or six working on Un in New South Wales, and doing well. \ Inquirer.— (l) The use of the term " esquire" j

quantity of honey taken out of a church I steeple in England, a paragraph about which appeared soni3 eight years ago." Anxious. — Yes. A week's notice must be given on each side. Southern. — A cavnot be compelled to pay B's i travelling expenses to Auckland. B can I apply under Section 91 of "The Magistrates' Courts Act, 1893," to have his evidence taken in Dunedin. Should B elect to attend the Auckland Court, and subsequently win the ease, tho court has discretionary power to award him costs of attendance. It is assumed, of course, that B is served with an ordinary summons — not a judgment summons. Bruce. — (1) An information mu«t be laid under

. negotiations for you. unless yo*a can go over yourself. yourself. If you decide to employ an Australian firm >ou will find the address of one in the answer to Colonial Boy elsewheie in this column. H. M. — (1) It is immaterial whether two or three cards are dealt first. Deal to your left. (2) The entire erea of New Zealand, including its dependencies, is 104,751 square miles, or 66,589,520 acres. The area of Great Britain and Ireland is 121,000 square miles. (3) The population of the British Isles in 1901 was 41,607,552, consisting of 20,166,214 males and 21,441,338 females. At the census of 1902 the population of New Zealand was 789,994, comprising 414,662 ir>ales and 375,332 females. This is exclusive of 13,143 Maoris ;