OUR PUBLIC SCHOOLS COLUMN

Otago Witness, Issue 3102, 27 August 1913, Page 72

OUR PUBLIC SCHOOLS COLUMN

FOR SENIORS AND JUNIORS. (Conducted by Magisteu, to whom all communications must be addressed.) [itagister will be glad to receive Nature notes, marked papers containing educational articles, diagrams, details ot experiments, etc., of scholastic interest to teachers and pupils. Correspondents must use ospy one side of the paper, and whether using a pen name or not, must send both NAME and ADDRESS. 1 NOTES FOR AUGUST. By J. F. Morris, Gatlins. During August the true sun comes to the meridian before the mean sun, consequently the true solar day will be less than 24 hours, and the equation of time the sun has to make up tins month is overtaken; in other words, the true sun, which was 82sec behind the clock on August 1, is only 4scc in arrears on September 1. This moans that the solar day and the sidereal rotation are still performed in nearly the same interval. Although the two movements are not, and could not bo strictly synchronous, yet the difference between the two movements ‘s very slight. On August 1 there is only 3sec between the two, and on August 29 17aec. By adding those amounts to the sidereal rotation, -you will get an ide-a of the length of the solar day. Now, what docs this imply? It implies a slower velocity in orbit. The extra amount of rotation which the earth has to cover in order io again bring the meridian to the sun, is proportional to the orbital velocity. The greater the progress the earth makes in its orbit around the sun on any given day, so much more will the earth require to rotate in order that any given meridian may again overtake the sun. Again, the slower the movement in orbital progress, the quicker the movement in “change of plane —i.o., from the plane of the solar equator, to the plane of the terrestrial equator, or from that part in the heavens where the ecliptic and equinoctial are furthest apart — 0.g., June and December—to that part where they intersect —e.g., March and September. This is indicated by the daily change in declination. Both factors indicate a loss of velocity in orbit—that is to say: (a) The approximation of the solar rotation (solar rotation of the terrestrial meridian) and the sidereal rotation (star rotation of terrestrial meridian); and (b) the comparatively excessive movement of change in declination at the approach of' the equinoxes, as compared with the slower movement at the solstices. Both movements, then, as already indicated, point to a considerable loss in average velocity in orbit. As a matter of astronomical observation, the June-to-Septcmber arc of orbit is the slowest section of the ellipse. It takes the earth 94 days to do this section, as against 92 days to do the March-June section. Of course, after September the earth approaches nearer and nearer the sun, and this fact increases her velocity considerably. On August 2 the sun will rise at noon at lat. 72 S.. after an absence of 82 days. On the same date it will be dawn at the South Pole. During August the sunlight increases 88min and the daylight by 78min, so there is a diminution in the amount of twilight by about five minutes morning and evening. But this is to bo expected as wc approach the equinox. But my promised article on twilight must stand over for a while. How Time is Regulated.—lt is a mistake to think that time is regulated by observations worked out from the sun. Time is regulated from observations, with a transit telescope, of certain wcUknown stars, usually known as “clock stars,” as they appear to come to the meridian—that is, as “ they cross the wires in the field of view of the transit instrument mounted in the meridian.” By these observations a sidereal clock is regulated to keep sidereal time. Now, if wo know the error of the sidereal clock we know the error of the mean time clock. The sidereal movement from day to day is a fixed amount —i.c.. 23hrs 56min 4.09054ecc, and the mean time movement is, as you all know, a fixed amount —24 hours. At Greenwich those sidereal clocks are regulated by fixing a tiny dish to the pendulum, and adding or taking away little weights to or from the dish. It can also bo done by a system of electro-magnets properly arranged. “ Thus it is possible to keep right within a small fraction of a second the clock at Greenwich, which sends the time signals to the General Post Office. Those signals are transmitted hourly or daily over the telegraph system to every post office, and can easily bo made to control public clocks or drop public time balls wherever the local authorities are sufficiently keen to provide the small outlay necessary to give their city really accurate time.” These Northern Hemisphere “clock stare” have been ingeniously arranged in a tabic, so that anyone in the latitude of

London could tell the time at night without a watch to within half an hour, or he could regulate his watch to within four seconds with a few evenings’ practice. Now we in New Zealand have a magnificent “ star clock ” Achernar Canopus, Southern Cross, and the Centaurs. I wonder how many of us have tried to arrange these stars in order to tell the time, and hence clock time, on any day of the year?

SHEEP. [I am indebted to “Teacher” for these notes, and am sure many country teachers will appreciate them. —“ Magister.”] Sheep live naturally in high altitudes. When attacked by enemies, they follow their leader over difficult and dangerous mount an paths and tracks. Observations.—(l) What is the chief character that separates sheep from other animals? (2) What is the difference between wool and hair? (3) Why is wool of special value to sheep in their native haunts. (4) Is there any hair on sheep? (5) Where do wild sheep live? (6) What is the climate in these places? (7) Does wool servo them well on this account? (8) W hat sort of pasturage do sheep find on mountains. 19) Could cows get a living where sheep thrive? (10) Describe the sheep’s teeth and how they are arranged to enable it to crop vegetation closely’. (11) W hat happens to the vegetation on the range when a large flock passes over it? (12) What are the chief enemies- of sheep in the;r wild state? (13) How do the sheep escape? (14) Describe the foot and the log of the sheep, and cxp’ain how they help the animai to escape its enemies? (15) We say that some people follow others “ like sheep. Why do we make th’s comparison ? (16) What has this habit of following the leader to do with escape of sheep from wolves and beans? (17) How do sheep fight? (18) Do both rams and ewes have horns? (19) Do they both fight? (20) How does the sheep show anger? Tell your experience with a cross lamb. (21) Do you think that sheep can see and hear well? (22) What is the petition of the sheep’s cars when it is peaceful? (25) Also, when there is danger? (24) How do the sheep’s eyes differ from those of a cow? (25) How do they resemble the eyes of a rabbit ? (26) Does the sheep chew its cud as the cow docs? Describe the action as performed, by the sheep. (27) How is the cud-chcwing habit of value to the wild sheep? (28) Describe a young lamb. Why has it such long legs? (29) How does it express great pleasure? (30) What happens to the tad later? (31) What games have you seen lambs play. Tell all the stories of lambs that you know. (32) How much of the sheep’s language do you understand? (33) What is the use to the flock of the constant bloating? (34) Docs the bleating continue when danger is near? (35) For what purposes do we keep sheep? (36) How many breeds of sheep do you know? (37) What are the chief differences between the English breeds and the mernos? (38) Describe the actions of a collie in looking after a herd of sheep? (39) Did you ever know of dogs killing sheep.? (40) At what t’me of day or night was this done? (41) Did vou ever know of one dog alone attacking a flock of sheep? (42) Can you explain why two or' three dogs, when hunting, give chase and attack sheep? Notes. —Sheep thrive best in cool drylocalities. In wild state- sentinels give warning of approach of danger. In top jaw the only teeth are grinders at the back. There are no top front incisors. There arc e : ght incisors in bottom jaw, and six grinding teeth at the back of the side of each jaw. Below ankle, legs are short and delicate. The part above the ankle has developed to help the animal in leaping (i.e., in wild state); hence the “leg of lamb” as a table delicacy. The Jog as descended from the wolf is the ancient enemy of the sheep. Read " Owd Bob.”

METEOROLOGICAL NOTES. 1 am sorry to have to cut these notes short to day. Note that the rainfall at Beaky Elat for July (15.20 in) is more than that at Ranfurly for the whole year; and the same remark applies to Ross records. Has the Ross school a maximum and minimum thermometer? If so, 1 shall be glad to ha>ye the maximum and minimum given also, for 1 presume that the average maximum and" nrnimum refer to 9 a.m. What place is acknowledged to be the coldest in Otago? What is the m'nimum recorded in Now Zealand? The greatest d’ —i:nf;d‘ v Monthly? Yearly? Wairoa adds a note: “On July 31 the willows were showing di-tinctly green, peaches and nectarines showing ear’y blossoms, and daffodils common.” I should likeregular notes from various localities, giving observational notes exactly defining the tloings of Nature. For instance, on August 2 I saw in Jubilee Park the flowering currant ready to burst its blossoms, and a willow in partial leaf Surely some schoo's are keeping regular data. If so, please send along abstracts. Runfurly, August 2. Dear “ Magistc-r,”—'The undermentioned arc the meteorological records for the month of July:—Maximum temperature in screen, 58 degrees on the 18th; minimum temperature in screen, 15 degrees on the 12th; minimum temperature on ground. 12 degrees on the 12rh; average maximum in screen, 45.45 degrees; average minimum in screen, 29.05 degrees; average minimum on ground, 26 degrees; rainfall, 160 points on nine days; maximum fall, 60 po : nts on the 2nd ; rainfall since January to date, 1267 points on 62 days: frost occurred on 24 nights in the screen, and on the ground on 28 nights.— Yours truly, A. W. Roberts. Wairoa, 11.8., August 4. Dear “ Magister,” —I have much pleasure in forwarding the following weather records for July:—Rainfall; On the 3rd, .02; 6th, .08; 6th. .30; 7th. .11; 11th, .13: 15th, .09; 16th. .03; 19th, .10; 20th. .35: 22nd, .37; 23rd* .01; 24th, 07; 31st, .18; — total, 1.84 in on 13 days; total for 1913 to July 31, 19.15 in on 74 days; corresponding period of 1912. 33.86 in on 95 days; and of 1911, 46.69 in on 101 days. For comparison—July, 1907, 7.96: Julv* 1908. 5.51; July. 1909, 5.30: July, 1910. 9.96: July, 1911, 3.83; July, 1912. 5.48;’ Julv. 1913, I.B4;—average for July, 5.69 in. Temperature: Minimum, 32 degrees on the 14th; maximum, 70 degrees on the 4th: average cf minima, 41.3 degrees; average of maxima, 60 degrees; average at 9 p.m.. 46 7 degrees; average at 1 p.ni., 56.3 degrees; frost on grass, 10 times. Barometric pressure; Uniformly hi"h. with one fall, to 29.57 on 21st. with very strong N.W. wind. On July 31 the willows were showing distinctly green, peaches and nectarines showing early blossom, and daffodils common.—l am. etc., JOHN Bo win 8.A.. Head Master.

Ross, August 4. The following is the Ross weather record for July:—Thermometer.—9 a.m. : maximum, 56deg; minimum, 36dcg; mean, 44.8 deg. Night: Maximum, 44deg; minimum, 30deg; mean, 36.4 deg; times 32 or under, two. Barometer: Maximum, 31.24; minimum, 29.68; mean, 30.46. Rainfall: Tot.d. 13.42 in; highest daily, 1.36 in. Number of days, 22. Wind; E, 6; N, 3; S.W., 1. Weather: A miserable month, only seven days of decent weather, the rest, raw, cold, wet W. Winchester.

Wyndham South, August 1. Dear “ Magister,”—The following are the metoorogical records for the month of July:—Rainfall: On the 2nd, .50 inches; 3rd. .03; 4th, .17; sth, .02; 6th, .05; 9th, .02; 10th, .24; 12th, .12; 13th, .12; 14th, .26; 15th, .08; 16th, .20; 17th, .01; 20th, .04; 21st, .31; 22nd, .08; 23rd, .18; 24th, .40; 25th, .84; 26th, .11; 27th, .40; 2Sth, .01; 30th, .01; —total rainfall, 4.20 inches, on 23 days. Thermometer: Maximum, 58deg, on the 18th; minimum, 27deg, on the 11th; average of maxima, 46.9dcg; average of minima, 37.0 deg; average temperature in the shade at 1 p.m . 44.8d0g. Frost occurred on seven nights Wind on 25 days; prevailing wind from the N. on nine days. Snow fell (the sixth fall for the season) on the 11th, .25 inches. Summary of rainfall since January 18th.—January, 2.62 inches; February. 4.38; March, 6.77; April, 4.44; May, 6.12; June. 2.94; July, 4.20; —total, 31.47 inches.—Youry truly. J. White. NOTES AND CORRESPONDENCE. “ North-East Valley ” wants same notes on how to keep rabbits. I haven’t given any before and do not know that 1 am competent to give expert advice. Plenty •jt intstles fresn, say. twice a day; lettuce leaves in season, end ether vegetables are all food os far as I know. A lad near me kept “pink-eyes” and. “lop-oars,” and these with some bread and milk occasionally

-vore all he used as food. Now and again it will bo advisable to let the rabbits have the run of a grass plot if possible, and the too nails ought to be kept trimmed. Be euro to keen the hutch clean and give frequent changes of clean straw. It is better, too, to have two compartments, one darker than the other, ihc other being well lighted and used as the dining room. If readers who have liad considerable experience in keeping rabbit 4 will forward any furt\.?r details I shall be glad.

I am glad to hear that Mr Joyce is willing to hand over his specimen to the Museum. Now and then I got something which is worth keeping. I am much obliged to Mr Tyndall for his interesting letter, and I should like more to know the name of the insect. What are its metamorphoses, etc. ? I thought I had some notes upon it, but I cannot find them. I have an idea that I hoard Dr Bmham describe it in a lecture. I must find out.

Middlemarch. August 11. Dear ‘‘ Magister,”—l know the insect about which “ Teacher ” seeks information. Ho is an ogre of the insect world, and treats poor, thoughtless flies as the cave-giant in “ The Pilgrim’s Progress ” treated wayfarers who jmssed by his residence.

One clear windy day last summer I noticed a swarm of blowflies settled on the bare lee side of a bank near a small stream, apparently basking in the sun away from the wind. As I approached many buzzed awav, but several remained seemingly glued to the soil. Some of those were dead, others feebly fluttering their wings. Picking one off, I descried a hole behind, from which protruded a savage black head armed with two incurved hooks. The miniature dragon Quickly withdrew his hideous head into the inmost recesses of his gloomy cave. I found the bank was studded with dead and dying flies, some largo, some small. Behind each was a dreadful head devouring them. The smaller flies were half in and half out of the holes, the big ones just held there by the curved mandibles of their foe as if pinned on a card. Evidently they had liphteomely settled on the sheltered slope to enjoy the sunshine, unaware of the hungry dragons in the tunnelled ground. Probably one of the reasons why the holes of the animal are usually seen in dry sunny scarps is that flies choose such places to bask in the sunshine. I have fancied that this terror to-flies is the larva of a wasp, but the holes are exceedingly numerous, and each, as a rule, soems to have an inmate. If a winged wasp comes from oach. wasps should be more plentiful than they are. I have r < yer seen the winged specimen of which “Teacher” speaks. T send you six of the beasts herewith. If they arrive safely you will notice each has a oncer hump on his back, armed with two hooks for excavating purposes, I presume. A W. Tyn’pat.l, p Xo, lam wrong alwut six. On looking into the box I find one has killed and mutilated a small comrade. i nc?y seem to be cannibals, and perhaps when you receive the parcel there may onK one left, the monopolist who will have doomed and nlisorbed : “The cook and the captain bold And the mate of the Nancy brig. And the bo’s’n tight and the midshipmite And the crew of the captain’s gig.” I found this after the typing of my story was done.—A. W. T.

Otokia, August 6. Dear “ Magister,”—l sec my old friend “ J.” (Rimu) wants to know if any of your correspondents have seen a black fan tails nest. Yes, I have, and it had five eggs m it. I saw a fine rod butterfly on July 9, and a black bumble bee on the 2nd of this month, also one to-day, the 6th. Plums and wattle trees are in full bloom out hero, and thrushes were seen building a fortnight ago. Most birds arc pairing now. This is a good season for lambs 20 dropped; no deaths so far; six pairs; no singles.—Yours truly, J- Shore.

Dear “Magister,”—This afternoon ns 1 was looking for cocoons I broke a slender twig which was hollow down the centre. Inside the twig was a chrysalis of a woodboring beetle. Its body is made up of 10 rings. On ite head it has two eyes, and a trunk like that of a fly. It has two wings, which are folded clofely to its body. Protruding from its head are two long feeler* which are lying down its sides. Its body is very long and slender, and is of a light yellowish colour. In another twig there 'were more chrysalides at different stages. We shall be able to watch the other changes taking place.—Yours sincerely, Reg and David.

Grey Valley, August 3.

Dear “ Magister,”—Though I’ve been silent so long, I have not quite forgotten you and your column. The Greymouth rainfall records will be of interest to you. Up to June 30 the rainfall' recorded was 50.12 inches, rain falling on 95 days, and in the month just ended 9.04 inches on 25 days, making the rainfall in Greymouth amount to 59.16 inches on days in seven months. The weather has indeed been very unsettled and changeable this year, and you may picture to yourself how damp and wet everything is, though, fortunately for us, the gravel is near the surface of the soil hero and the water runs away quickly. The two topics discussed everyweherc on the West Coast these days are the recent Grey election and the weather, and many and varied are opinions expressed on both subjects. Why should folk compain of our weather? It might have mined on 31 days in July, instead of on only 25 days. There’s never a bad, but there might be a worse. It seems human, nature to grumble and growl about it, and, to bo frank, I own .to being very human myself. It has been mild the last several weeks. Every growing thing is showing signs of awakening life. Early those mornings it is a musical treat to hear the thrushes singing. What a wonderful variety of notes and trills those feathered songsters possess, and how sweet their liquid melodics areI am enclosing a local newspaper clipping anent the rain record at Bcal.ey. The figures thereon are interesting. Hero there has been rain every day so far this month, which looks well. This is a glorious afternoon after a fog, and it is to be hoped the weather conditions are to be Improved, for, to say the least about it. we’ve had a trying time the last few weeks.—Yours, with kind

regards West Coaster. [The following is the dipping:—“Compared with other years, the month of July at Bealey Flat was a very wet one. Frosty and dear weather is generally experienced at this time of the year, the rain usually not setting in until mid-August. Several falls of snow were experienced, but none was of a severe nature. Rain fell on 22 days during the month, the maximum fal 1 being 4.78 in, recorded on July 2. The total rainfall for the month was 15.20’n, as com•pared with 8.20 in for July, 1912.’’]