OUR PUBLIC SCHOOLS COLUMN

Otago Daily Times, Issue 15764, 15 May 1913, Page 5

OUR PUBLIC SCHOOLS COLUMN

FOR SENIORS AND JUNIORS. (Conducted by Magisteb, to whom all communications must be addressed.) [MiQisTtn wiU be glad to reoelie Nature notta, marked papers oontaiuing educational articles diagrams, details ol experiments, etc., ol sobolastic Interest w teachers aod pupils. Corrospoudenu must use (SLV oxi stun ol toe paper, and whether using a pen uaine or not, must »ud boUi XAUK uud ADURBB3.J REFRACTION. Mr Morris, in ms notes to-day, malra mention oi Kcliaction. \vnat s reiractioi); Ijgnt ravs passing irom one medium into a uensoi'onc or into a denser part of t-ne same ni'.d urn become bent; consequently. ai< tno air at ci:c suriaoo ot the eartli is denser fntiii it .'» mgiK-r up-ieiucmoer iliat just as risli move about on the -bottom ol tno ocean ol water we move about on tlie bottom of an ocean of .air—rays from the sun at sunset, sinking the higncr regions of the air, are bent towards us by the denser air below, so when we see the sun on the horizon we are actually looking along bent rays coming from the sun twin below the horizon. Wo might almost say we arc lookmg around a coiner—at anyratc. we are looking around a curve. Mow for a simple experiment for boys and girls. Get a Dig billy or basm; place a shillinjr—anything will do-on the middle of the bottom; stand back until it is just lost sight oi and remain steady; then get someone to keep the shilling from moving bv pressing a pencil on it, and then wi_th the other hand let the person gradually fill the basin or billy with water. Before the receptaclo is full the coin will becomo visible though it has not moved. Iho rays of light parsing from the eye, into the basin, and beyond the coin, are retracted or bent, and fall short of the coin. Notice a stick or a rush at an angle in water, , and the same effect is seen. NOTES FOR MAY. ( J. F, Morris, Catlins.) The sun is still advancing along the ecliptic towards Cancer; and the Northern Hemisphere is now in the full enjoyment ot the sun' 6 heat and light. At_ the beginning of the month the midnight sun would be visible anywhere between the North Pole and 76 degrees N. latitude. At the end of May the sun will be above tho horizon, absolutely and relatively, during the whole 24. hours, to all those regions between the North Pole and latitude 68 N. There will also be a corresponding widening of the twilight belt. Midnight twilight will extend as far south as the fiftieth parallel of north latitude. Vancouver, Southern Canada, Newfoundland, -will all be in the enjoyment of midnight twilight. There will also bo twilight from sunset to sunrise in Scotland as far south of the parallel of Edinburgh, where there will be 17 hours sunlight, and 18 hours sunlight in the Shetland Isles. At Dunedin the twilight belt during May stands at lhr 52min approximate. This is only a few minutes above the time value of the mean width of the twilight belt. The mean width of this arc (as we have already seen) is 18 degrees. Transferring the Dunedin parallel to tho Northern Hemisphere. I find that at the end of May the twilight belt will be,39 degrees or arc, or more than twice the mean width. This is equal in time to 2hr 36min. There is therefore 2hr 36min of twilight right across Europe from Bordeaux, over the Maritime. Alps, along the military frontier of Bosnia, and on to Roumania through Belgrade. Of course, in the Southern Hemisphere, the reverse of this will take place. By tho end of May the sun will have disappeared from latitude 68 S. Midday twilight will extend.from 68 Stoß6 S. From 86' S. to the Pole will be in the grip of tho Antarctic darkness. Our friends at the "wireless" station down at the Macquarie Islands have a very short oeriod of sunlight—sunrise 830, sunset 3.42. They have, however, a little more twilight than falls to our 6hare. I Theirs is about 2hr 15min.

'Jlie calculated refraction for May is SSmin ol arc:—Adding Solar disc IBraiii we got 72min. 'Jliis is cqn.'il to -lmiii • 48sec. I*ho Sun will therefore appear to rise sooner, and set later by that amount. Twilight time as printed. OUR METEOROLOGICAL NOTES. Our records are increasing in number, but what- iias become of Winchester's and ,\Vost Coaster s records. The rainfall records are interesting/ this month, and would be more so if wo ' could procure two or three more North Island records. What was it at Taupo, New Plymouth, Thames,' and Auckland? I haven't seen the Gore record for April, but it must be much higher than usual. Mr White, of Wyndham .South, gives one reason for the devastating waters—the melting of snow with the warm rains, and is not very reassuring when he mentions traces of much higher records and points out the possibility of warm winds and rains and melting snows in early spring, when there will bo 60 much snow to come away. Note the 7.63 in for March out of 11.79 in for the year at VVairoa (H. 8.), and the diminishing record for the first four months in the Just two years—l9li, 25.24 in; 1912, 15.29 in; 1913, 11.79 in. The/lays on whicn rain fell was also a decreasing number—47, 45, and 41.

Tawaiwi School records are our latest addition, 1 assume that though records arenoted only once a day, the maximum and the' minimum are self-registering records, and not the actual record at 9.30 a.m.

When ihe April iitrures for the dominion come out I imagine that the Hermitage records will stand among the highest, for 21.93 in are reported as having fallen on four days, and 19.10 in of this in two days. How many gallons and how many tons dors this downpour represent to the acre?

By the byo, I asked a fortnight ago what the catchment area of of the Mataura

i>. Mr White makes it out as 1300 square mite, not. including any of the basin below Gore. . What docs that represent in tons and

gallons on a 4in basis? Tako 277J cubic inches to a gallon, and a gallon at lOlbs. fn one of my notes I advised teachers taking an interest in meteorology to apply to the director of the Dominion Meteorological Department fpr a 6et of instruments. One teacher in Otago applied as I suggested, and reoeived the following reply Irom the director:—" Dear Sir,—l regret lo say that it is against the regulations ot this department to supply schools with rain gauges. On account of the frequent holidays, and the. irresponsibility of the pupils and removal of teachers, our experience with schools has been unsatisfactory in the past." I am sorry to read this, and can now only suggest that our Education Beard be approached for sets, or, at any, rate, for half cost. Raufurly, May 1, 1913. Dear " Magister,"—The following are the meteorological records for the month of April :—Maximum temperature in screen, 69 degrees on the 17th; minimum temperature in screen, 22 degrees on the Bth; minimum temperature on ground, 19 degrees on the Bth; average maximum in screen, 56.13 degrees; average minimum in screen, 33.83 degrees; average minimum on ground, 31.4 degrees; rainfall 198 points on six days, maximum fall £0 points on the 15th; rainfall since January to date, 923 |x>ints on 37 days. Frost occurred in the screen on 13 nights, and on the ground on 19 nights.—Yours truly, .A. W. Robeuts. Wairoa School (H. 8.), May 1, 1913. Dear " Magister,"—l have much pleasure in forwarding the following weather records for April :-Kainfall: On sth, ..86; 6th, .35; 7th, 1.30; Bth, .52; 9th, .93; 10th, .06; 14th, .95; 17th, .14; 18th, .68; 19th, .17; 20th, .01; 21st .36; 24th, .04; 26th, .01; 27th, .17; 28th, ,06; 29th, .01; 30th, 1.01;— total, 7.63 in on 18 days. Total for 1913, to 30th April—ll.79in on 41 days. Total for corresponding period of 1912—15.29 in on 45 days; and of 1911—25.24 in on 47. days. Seven years' average, April fall—6.oßin. Temperature: Minimum, 42 degrees on 16th'; maximum, 77 degrees on 7th j average of minima, 49.3 degrees; average of maxima, 65.5 degrees; average at 9 a.m., 65 degrees; average at 1 p.m., 61.5 degrees. Atmospheric pressure: Uniformly high; a record maximum being recorded on 22nd of 30.85, which surpasses by nea.rly two-tenths of an inch any record for the past nine year. Minimum, 29.9 on 30th.—John tiowiE, 8.A., Head Master.

Miller's Fiat, May 1, 1913. Dear "Magister,"—The rainta.ll for February was l.Di inches, [or March' 4.93 inches, aim for April 3.U2 inches. Average thermometer: February 67.5 degrees, March 60.5, April 51.5. Greatest heai, 8b degrees ui the shade, on February 6. The uarometcr ranged from 28.6 on February 15 to 30.2 on April 7.—Yours, etc., Jas. Smith.

• Tawanui School, Catiins, May 6, 1913. Dear " Magister,"—Herewith please hnd weather records 1 have taken at this school during April. I lorgot to take a lew barometric readings, so am unable to supply these this month. Headings aru taken aauy about 9.30 a.m.. Kaintall lor month, 5.21 incites; number of days on which ram tell, 16; highest rainfall tor 24 hours, .76:n on 29th; maximum ■ tomparature for month, Ti degrees on 9th and 27th; minimum temperature for month, 32 degrees on 17th, loth, and 25th; average of maximum temperatures, 60.2 degrees; average of minimum temperatures, 40.5 degrees.—Youth faithfully, John G. Johnston 1 .

Wyndham South, May 2, 1913. Dear " Magister,"—The following'are the meteorological records lor the month of April:—Rainfall, 4.44 in on 16 days, as follows: Ist, .21in; 2nd, .27in; 3rd, .40in; 4th, .66in; sth, .18in; 6th, .09in; lltn, ,36in; 13th, .82in; 11th, .07m; 15th, .03in; 16th, .45in; 19th, .03in; 20th, .Olin; 23rd, .04in; 29th, .68in; 30th, .14in. Maximum thermometer, 64 degrees, on the 27th; minimum thermometer, 34 degrees on the 13th and 14th; average maximum thermometer, 54.5 degrees; a,verago minimum thermometer, 40.6 degrees; average temperature in the shade at 1 p.m., 51.6 degrees. Wind on 18 days; prevailing wind from the west on 9 days." A double shock of earthquake was recorded on the 26th at 10.7 a.m.-Yours truly, J. White. P.S.—ln re your inquiries last month. lam using a.eelf-registering maximum and minimum thermometer. Last month the average maximum and minimum were not sent. This may have been misleading; they were 60.9 degrees and 46.6 degrees respectively. With regard to the Mataura flood area, I compute it (by scale) as, north of Gore, '1300 square miles (approximate). _ The flood waters of the Wyndham and Mimihau tributaries did not materially affect the flood level, since both had subsided considerably before the Mataura flood came down. I do not give any credence to the statement that 4in (was it"') of rain wa6 recorded for 24 hours. I recorded 1.20 in on the 27th, and I.46iii on the 28th, and thits tallies with tho amount recorded by Mr Lennie, Invercargill. North of Gore the fall was slightly heavier, but certainly nowhere approaching 4m for one day. The quantity of water released by the warm rains melting the snow on tho mountains probably accounted for more than half the deluge. Had the flood occurred in September, when the mountains are heavily snow-clad, the dieaetcr must have reached appalling proportions. Thoughtful people are asking themselves if there is any security against such a spring flood. Tho late Dr Menzies has pointed out evidences of a much higher flood which mu6t have occurred within the century. It had surpassed the recent flood by six or eight feet. .Imagine the consequences of that amount of additional water at Gore! Graven on the river plain itself arc signs of previous floods which must have dwarfed even that. At the same time it must be remembered that the Mataura at one time drained Lake Wakatipu; thus it is now, to some extent, robbed of its powers.

THE MONSOON RAINS OF INDIA. Throe or tour months ago I ran out a note upon "' Problems and i'coplo of India," and in it I made reference to the monsoons, but it has been crowded out. Perhaps today is a good time to give it, and 1 (five it exactly as I wrote it then. Lot rne recommend to teacher*—to others, too—" Problems and Peoples of India," one of the shilling ntit series—ls 3d hcre-ot Williams aJid Norgatc. 'ihc first chapter fits in well with meteorology, and is all the better book for teachers because not written for teacliere. "Shoppy" books arc generally uninteresting to the ordinary reader, and are too dull and mattor-of-faoc. Moiklojohn's New Comparative Geography is ono of the exceptions; but even books of this class one docs not sit down to read. Ono reads with pleasure and, incidentally, with profit, such books as "Problems and People of India," even though one has Obtained the information before in some other form.

But before I refer to the monsoon, let me show briefly from this little book how the idea of water bulks big in Indian names and economy. Western Rajputana haxdly supports five persons to the t-quare mile, but the Gangetic plain supports up to 500 or more- on the same area.. "India" comes from the Sanskrit " Sindhu"—fame as Scinde?—literally "river" or "flood," "a name Kiven by the early invaders of India to the great river on which they settled

when they entered the plains country from the Jiighlands of Central Asia. To-day tins | river is tho Indus." They knew of nothing | bevond. ' "Without tho Indus and its streams the plains of Northern India would be uncultivated and uninhabitable I'lio same -truth ia expressed in the name ' Punjab' . . . literally 'tho land of the five rivers.'" THK HIMALAYA BEGION. Take the word "Himalaya." This means " tho abodo of snow." "As tho rivers of Northern India give food and pasturage to tho immigrants from Central Asia, the snowy rampart that closed them in on the north gave food to their imagination. They placed the seats of their gods in tho Himalaya, and they saw in them the mysterious source of their beloved rivers. The ice-cave in which' tho Ganges rises among the high snows became to later fancy tho matted locks of Siva, the great gcd of life and death. . . _. Tho instinct was a right one. It anticipated the reverence with which wo with ampler knowledge regard these inaccessible peaks. In them are fashioned the rivers which give life to the plains of India. Tho melting of their snows in the early _ summer causes those rivers to rise, and thus provides an unfailing supply of water for the great canals tot irrigate tho country. Liter on in the year, the Himalaya play another part. They intercept -tho vapourladen winds as they blow across India from the equator, and compel them to discharge their burden in fertilising rain." The writer then goes on to say: "The historian sees in the Himalaya a wall of seclusion which has kept Indian civilisation as a thing apart and given it a unique flavour. The statesman views them re a barrier between the warm and fertile plains of India and hungry prowlers without," though it can be turned at both ends. Further on we read: ihe Himalaya seem at first sight to provide a clear frontier line. They look on a map like a continuous rampart; they suggest that India, might stop where they rise from the plains. But a large scale map on examination shows that the Himalaya are not a single range of mountains, but many ranges, and that the political boundary is laid far in their recesses. Ihe rea line includes from east to west an averago breadth of 100 miles of the mountainous region of the Himalaya," . Again. They are a part of a- great mountain region where range folows range, and where the water parting lies behind. the central range of snows. The Himalaja Mountains, which tower above the plains of India, in a continuous line of snowy peaks, are but the wrinkled southern edge of the great Tibetan plateau. Their highest range is at a distance of 80 to 100 miles from the plains. Behind the snow line is a deep depression or trough, in which west and east fed by glacial streams run rivers which eventually terminate in India. Westward runs the Indus, and eastward a river which, in India becomes the Brahmaputra Both rivers take their rise r.car the g aeial lake of Manasarowar and the peak ot Kailas, names among the most sacred ot Hindu mythology. The Indus bursts into India at Attack, near the military station of Peshawar, after a journey of 700 miles in its rocky cradle in tho mountains. Die Brahmaputra enters Assam after a still longer course. The trough which thus conveys them to India in onpos : te directions is one of the most remarkable in the world. . . To the north of it is the tableland of Tibet, the most elevated region of its kind in the world.. Its average elevation is from 15.000 ft to 18,C00ft above the sea-a height surpassing that of the loftiest mountains of Europe [substitute Mount Cook to localise tho comparison]. Its -width is from 300 to 400 miles. Geologists have shown that the Himalaya and the Tibetan plateau are essentially one formation, and are due to the same cause. In comparative recent times, as geological periods go, this portion of tho earth's surface was forced up by contraction of the crust. The IndusBrahmaputra trough is a mere crack '>r scratch in the surface of this vast elevated

region." But' I promised a note on Monsoon, which, after all, condensed and removed from its context, may not amount to •much. The word is an Arabic one, meaning "timos" or "seasons." ''A monsoon is a seasonal wind, that is, one which blows continuously from a certain quarter curing a certain period of the year; and a monsoon region is one in which the climate is entirely controlled by winds of this kind. India is such a region. It has well defined seasons of rain and clear skies, and.these depend upon conditions of atmosphere and temperature not in India itself, but :n the Indian Ocean and adjacent lands. Broadly speaking nearly the whole rainfall of India U confined to about three or four months of the year. From March to June the Indian continent heats up, and the pressure of the air over the heated surface becomes less than that over tho Indian Ocean. Similar conditions prevail in Africa. A strong indraught is thus established in 'he land masses north of the equator, and currents of air laden with moisture from the southern 6cas pour across tho line, and bring about the rainy season, In the greater nart of India this season lasts from thi middle of June to the midd o pr end of September. In Southern India somewhat different conditions prevail, and the rainfall is chiefly in the latter months of the year. If the monsoon current is of normal strength and persistency, the'harvests will bo good and the cultivator will rejoice. If it is weak and short-lived there is drought and famine. The monsoon, therefore, is the dominating factor in the Indian year. Not only does the monsoon current Vary in strength from year toycar, but its distribution in India itself is ex-

tremely unequal. It is a thing of twists and turns, very sensitive to local conditions. If it strikes ilills it dissolves in of rain, but over a flat country it passes without expending a shower. [Localise by referring to the Canterbury Plain and Bealey.] A large part of North-western India, for instance. is practically rainless—either desert or dependent upon irrigation from the 6now-fed rivers. Bengal and Assam in the east are tracts of superabundant rain.'" In the latter place 600 inches and more of rainfall have been registered in the year. Now, that is more than I intended to write, but I think it illustrates the necessity for teachers to keep up their reading if'they want to present the latest information in the most attractive manner, and with such series as the "Home University Library " there is no excuse for one to be behind the times.. THE OTAGO INSTITUTE. I should like to draw the attention of teachers to the winter course of lectures arranged for by this institute. Within the last two or three years there have sprung into existence what might be called <t Technological Institute and an Astronomical Society; but these have been merged into the Otago Institute, with'the result, that a member has admittance to 20 or more meetings and the yearly volume of the " Transactions of the New Zealand Institute." Read this syllabus and 6ee if thcro is not much in it • which can be touched upon in school work: "Modern Alchemy and Radio-active Change." (Dr J K. H Inglis);_" Stewart Island," with lantern illustrations—largely botanical. I amagino (Mr D. L. Poppclwcll); "Light" (Mr E. E. Stark); • " The Carrier Problem in Infectious Disease " (Dr S. T. Champtaloup); ''Old Clocks and Watches" (Mr F. W. Payne); "History of Astronomical Researoh" (Mr R. Gilkieon); "Reflecting Telescopes" (Mr F. W. Payne); "Objects of Interest in the Evening Sky in the Month of June " (Rev. D. Dutton); " New Instruments and Methods in Solar Research" (Rev. P. W. Fairclough); "On Finding Latitude and Longitude" (Dr P. D. Cameron); " Coal Mining Operations" (Mr L. 0. Beal); " The Evolution of Artillery " (Captain S. G. Sandle); "Modern Methods of Heating Buildings " (Mr G. W. Davies); "Mechanical Refrigeration" (Mr J. I-J. Scott); "Dosign-irom a Technical Standpoint" (Mr R. N. Vanes); "Improvement Works in Otaeo Harbour" (Mr J. Blair Mason). In addition to those there are-three or four evenings devoted to short papers and exhibits. It seems to. rao that teachers cannot afford to miss such lectures as these, for in such lectures we have given general surveys from specialists, surveys which are necessary to busy people who wish to keep abreast of the la'test results of scientifio research.

MAY, 1913. DnsEDis Latitude. Twilight Sunrise. ?nnset. Ends, h. m, s. h. m. f. li. m. s. 1 7 1 12 4 52 51! G 42 24 2 7 2 28 4 51 21 G 41 4 3 ..i ... 7 .1 41 4 43 47 (1 39 35 •1 7 i 59 4 48 27 (1 38 23 5 7 fi 13 I 47 " 1 6 37 !) B 7 7 28 4 45 3G 6 35 56 7 7 8 44 4 44 12 6 34 44 S 7 9 5G 4 42 52 6 33 32 3 7 11 8 4 41 32 6 32 24 10 7 12 25 4 40 9 6 31 9 11 7 13 3!) 4 .'18. 51 6 30 3 12 7 14 43 4 37 37 G 2S 57 13 7 IB 00 4 30 24 G 27 5G 14 7 17 16 4 35 8 G 26 52 15 7 18 23 1 33 53 G 25 51 IB 7 13 3H 1 32 48 G 21 52 17 7 20 41 ' 4 31 45 G 24 1 13 7 21 51 4 30 34 G 22 58 | 10 7-23 1 4 29 33 fi 22 5 20 7 21 7 4 28 31 li 21 15 21 7 25 10 1 27 31 fi 20 2G , 22 7 2G IS 1 2fi 3( R JO 38 I 23 7 27 22 4 25 38 6 18 50 ! 21 7 28 27 4 24 43 G 18 3 25 7 23 23 4 23 52 G 17 20 2G 7 30 2G 4 23 fi fi 10 4G 27 7 31 3.'! 4 22 13 fi 1G 5 28 ■ 7 32 3G 4 21 24 6 15 20 20 7 33 23 4 20 51 6 14 55 30 7 31 27 4 20 3 G 14 15 31 7 35 15 4 10 31 fi 13 51 Jwic 1 ... 7 36 12 4 18 52 fi 13 20