NOTES AND QUERIES.

Otago Witness, Issue 3662, 20 May 1924, Page 43

NOTES AND QUERIES.

Questions for reply in coming issue to be re* •eived not. later than SATURDAY night. Questions will NOT bo replied to through the post. "Stamps'’ asks how many stamps there are in the world. That is, if a person could have a complete collection (all different) of all the known stamps, how many would he have? The total ordinary issue_of stamps to November, 1923, was 38,927. In addition to these there have been special issues in some countries, but the above total represents the ordinary postal issues. "Interested” a3ksWhat is the best method to employ to kill large willow trees growing round a dam, and the most favourable time of the year to apply the remedy? Bore holes in the leading roots and fill with sulphuric acid or weed killer. Any time of the year may be chosen. "Romeo” asks if there are any places in Dunedin where one can have one’s hand or character read, and if so what price is charged. The practice of foretelling the future is unlawful, and though doubtless it is carried on we cannot supply any information on the matter. “Amateur” asks for a recipe for. flour paste for paper hanging. M ix one quartern of flour, one quarter pound of alum, and a little warm water; when mixed, the requisite quantity of boiling water should be poured on whilst the mixture is being stirred. When used it should be spread on one side of the paper, which should then he folded with the pasted side inwards, and allowed to remain a few minutes before being opened and used. This swells the panel-, and permits its being more smoothly and securely used. “H. W. 8.,” Teviot. —Mr H. M. D-avey^ l consulting engineer., replies;—Rope belting can be easily and cheaply used for quick speeds. In speaking of speeds for quick speeds it is best to get at the speed per minute of the rope rather than the revolutions of the pullevs as a small pulley, if a driving one, would give a slower speed than a large pulley, if the revolutions were the same. It seems to have been found that that about 4800 ft per minute gives the best result for these belts or driving ropes. Experiments have been made driving the ropes up to 7000 ft per minute, but the results were getting poorer as the speeds increased above the speed given above. This seems to be that the centrifugal force of the rope, when running round the pulleys, really tended to lift the rope off the pulleys when the speeds were so high. At the speed of 4800 ft per minute a rope Jin in diameter (an ljin one) gave eight and a-half horse power, and a 3in one (lin in diameter.) transmitted 11J horse power. To get the rope speed of 4800 ft per minute a pulTe'y about 3ft 3in in diameter, or say, 10ft in circumference would only need to revolve 480 per minute—no very great speed—to effect the result. If you require more information write again, and to the editornext time, please. “Blackstone Hill.” —Mr H. M. Davey replies: This is one of the very extreme "accuracy” questions, and is this, "Is the surface of a cup of water level or not?” You probably seem to mean, ‘‘ls the surface of water in a cup (or other vessel) level?” Generally one might sav yes; but probably the exact truth would be otherwise. Now if the water were verv carefully poured into the said c-up and the cup was perfectly drv the edges would be depressed, by friction with the sides of the cup. You could verify this by carefully pouring liquid over any very dry surface. The liquid stands up, and you can surround a level surface with it. the liquid forming a wall all round. Then the surface itself is higher in the middle as the ear.th is round. But if the surface of the cup were wet the result would be different, the edges would (I believe) rise up about as much as they were depressed in the dry one, by capillary at-

traction, and the surface itself would rise in the middle to suit the roundness of the earth. “Tutankhamen,” Hyde.—Mr H. M. Davey re‘ plies:—One would think you would' not care to look at a penny- with your riches, but your question is of great interest, and it is this;—“When a penny is put into a saucer slightly below eye level and so that it cannot be seen when looking at the saucer edgeways, it can be seen if the saucer is filled with water, and you ask why this is.” The reflection of the water seems to make the difference. I may say that I tried the experiment, and mounted the penny on a bit cut like a slice from a cork, which lifted the penny up, but so that a straight ruler laid over the edges of the saucer did not touch the penny, for that I suppose is what you really mean, although you show it at the bottom of the 6aucer. “R. S. 5.,” Roxburgh.—Mr 11. M. Davey re' lilies:—“With regard to your inquiry as to the best and simplest way to tell the capacity of various receptacles, I would ask you to remember one fact that will be of assistance to you at all times in this matter. Water weighs exactly 101 b per imperial gallon- therefore half a gallon is 51b, a quart 2lib, a pint ljlb, and a half pint lOoz. Any container, if weighed on a scale that has a pan on one side and weights on the other, is best weighed by balancing the empty container with a lighter basin, adding water enough to balance, thus leaving the weights free, and the capacity is found by tbe above tables. Thus a five-gallon tin should hold 50lb of water. If this does not fill it, you might make a mark where a given number comes to, so as always to know that quantity, you could mark where each gallon comes to. For a spring balance or patent scale it is better to add weight to the empty container to a given number of pounds. Thus, if the jug weighed 9jlb, add enough to make it 10lb, and then proceed as above. I have heard persons who ought to know better say that a pint of water and a pint of milk are not the same bulk; but that is utterly wrong. True milk, like oil. is lighter than water; but a pint is a measure of capacity, and a pint of melted lead, oil, or water, though of vastly different weights, have the same bulk, and fill the pint pot to the same height. The reasons for obtaining the capacity by means of water are that it is better .and cleaner to handle water than expensive liquids, and also that water, weighing exactly a given number of pounds to the gallon, eases the calculation as you will readily see. lam afraid that if you will try various tins, jugs, bottles, etc., you will find that the capacity is often very scrimpy, and in some cases much below the mark.” “Subscriber.”—Father M'Carthy’s Christian name is Thomas. He was educated at St. Patrick's College, Wellington, and at the Seminary, Meeanee. “Curious” asks if -it is cor,rect for a father to be asked at the cemetery to help lower his wife’s coffin into the grave when there are brothers, sons, and son-in-laws who could have officiated. Matters of such deep personal interest are in most cases mutually arranged beforehand, and the feelings of those suffering keen grief ar® invariably considered. “Bible” asks the prevent value of a religious book 300 years old, in excellent preservation. being a lengthy dissertation of the four Gospels, about 300 pages. In the absence of particulars—author’s name, publisher, etc.—it is impossible to advise. “Subscriber,” Otekaike.—The nock you sent for examination is reported by ProfessorPark to be a quartz gritstone of which the matrix or cementing medium is carbonate of lime. Quartzose grits usually occur as one of the lower members of the Crown coal measures. “X.” writes:—“ln blowing out the black mouthpiece of a tobacco pipe stem with a steam jet from a boiler a blue spark appears just like an electric spark. Can you explain?” When the air or steam is blown from ebonite stem the friction produces negative electricity on the ebonite and positive electricity on the air. As this air travels for a short distance through the stem it will become more highly charged, and it will have its highest charge when leaving the stem. Now as electricity escapes most readily from points or edges the electricity then would jump between the air and the end of the ebonite, and So cause the spark. “Mount Barker” asks particulars of the deadly nightshade. Says; “Some years back the newspapers eloquently described a. wonderfully prolific new berry and called it the wonderberry, for jam and eating, and then someone described it as a fraud, and only the nightshade. I would be glad of some particulars. The nightshade bore is becoming a weed, and the children are warned against eating the berry.” The nightshade is a common plant m damp hedgebanks and thickets, scrambling over underwood and hedges. It has slender, slightly woody stems, with alternate lanceolate leaves more or less heart shaped and auriculate at the base. The flowers are arranged in drooping clusters, and resemble those of the potato in shape, although much smaller. The flower clusters spring from the stems at the side of, or opposite to, the insertion of a leaf. The flowers are sucoeeded By ovate scarlet berries, Jin long, which in large doses aiipea l ' 1° be poisonous or, to say the least, dangerous to children, cases of poisoning by them having occurred. There are several varieties. Deadly nightshade, dwale, or belladonna is a tall, bushy herb of the same natural order. It grows to a height of 4ft or 6ft, having leaves of a dull green colour, with a black shining berry fruit about the size of a cherry, and a large tapering root. The entire plant is highly poisonous, and accidents not infrequently occur through children and unwary persons eating the attractive-looking fruit. Parts of the plant are extensively TfseJ fti medicine. “ Subscriber.”—ln our last issue we printed a lengthy article, “ Tanning Skins and Hides,” which covers your question.