108 



KNOWLEDGE 



[March 10, 1883. 



iiinoty-nino out of pvo-y tlioiisnnd men who have hail what 

 is called a classical education even read — to say nothing of remeni- 

 l>ering ? This is true oven amouf; men who take honours in classics 

 nt our Universities. Taking at 1,000 the number of youtlis wlio 

 take a degree each year at our Universities (a most unfair selec- 

 tion for my argument), how many does the llcv. U. Smith suppose 

 to be good scholars (even in his apparently rather restricted sense 

 of the words), and of these how many know much about the wise 

 payings of men of old times 'i The outside of the cocoa-nut is 

 laboriously scraped, and here and there a grain or two of the fruit 

 may be got out, though spoiled by the scrapings of the shell ; but 

 how maiiv learn the true Havour of the solid and liquid food within ? 



-RP-]" 



THE R.illSFALL OF 1882.— DURATION OF SUXSHIXE. 



1^756] — Perhaps some of your readers would contribute a few 

 notes on the rainfall of the country 'i Fresh evidence of the com- 

 jrarative wetness of different parts of these islands would be 

 valuable. At Killarney, five miles to the N. of the summit of 

 Mangerton, and eleven N.E. of Carntual, the rainfall for 18S2 was 

 58'5 inches ; in the Gap of Dunloe, near the top of the Upper 

 Lake, it amounted, for the eight months ending Jan. 2, 1883, to 

 06'6 inches. 



While on the subject of comparison of climates, may I add that 

 it is very desirable that some instrument cheaper in price for 

 recording the duration of sunshine than the so-called Campbell 

 Sunshine-recorder sliould be invented. There is no use, for 

 purposes of agriculture, ic., in obtaining statistics of the maximum 

 heat in the sun, unless we are also enabled to compare localities 

 4»nd years inter sc, as to duration of bright sunshine; and £10 to 

 £12 is a high price for an instrument of this kind. 



G. B. Wyx.ne. 



THE WEATHER PROPHECIES. 



[757] — Having read with much interest the remarks on tins 

 subject which appeared in Knovvleoge some few weeks ago, I 

 have, during the past month of February, been t.aking daily obser- 

 vations, in the hope of possibly throwing a little further light upon 

 the disputed question of the value of these forecasts. 



The plan adopted was similar to that of Sir Edmund Beckett. I 

 <livided a sheet of paper into two columns, placing on the left the 

 daily forecasts for " England, N.E.," and on the right, the weather 

 as observed at Newcastle. I will not trouble you with the tabular 

 statement, but will merely submit an epitome of the result. They 

 are deduced from twenty-three days in February ; four of the 

 others were Sundays, when no forecast was at hand, and on the re- 

 maining one, the 13th, 1 inadvertently omitted to enter any record. 



I have had regard to these elements : — (1) The direction of the 

 ■wind ; (2) Its intensity, and (3) The amount of rainfall. 



1. The Direction of the Tl'ind. — This is, as a rule, not very 

 precisely foretold, but is given as lying between certain assigned 

 limits, e.g., " S. to S.W.," and there is, therefore, difficulty in esti- 

 mating how far each prediction has been fulfilled. My method was 

 as follows, and, though open to the objection of being arbitrary, it 

 serves, I think, to give a good general idea of the success of the 

 prognostics. I arranged the results in four series, A, B, C, and D. 

 When the average direction of the wind for the day lay between 

 the prophesied limits, I put that day under A. When the direction 

 deviated from the mean of those limits by less than 45° (one-eighth 

 of the compass), I put the day under B. When it deviated by more 

 than one-eighth but less than one (|uarter of the compass, I put it 

 under C, and when by more than a quarter, under D. Here, then, 

 aire the total number of days in each series : — 



A B C D 



11 5 3 1 



I shall be inclined to call A right, B nearer right than wrong, C 

 nearer wrong than right, and D altogether wrong. In half the 

 cases, then, we may fairly say the prophets were correct, in eight 

 they were doubtful, and in four they were complete failures. A 

 striking instance of the latter occurred on February 17th, when a 

 etrong cold E wind blew over Newcastle the whole day, though the 

 office announced " S.W. or S. winds." 



2. Intensittj of Wind. — The forecasts under this head were mostly 

 too vague to admit of close criticism. Thus : — Feb. 21. " Moderate 

 to fresh or strong." The most definite predictions were those for 

 gales, and these were remarkably accurate. Thus gales or strong 

 winds were foretold on ten days, and on eiglit of these we had them. 

 The total number of very windy days was ten, seven of which had 

 <)een predicted. Thus on only two days was a gale predicted which 

 did not come ; while out of ten gales actually experienced warning 

 had been given of seven. 



3. Rain/all. — Here the Office seems to have gone lamentably 

 aetray. Out of eleven days whereon rain was predicted it only fell 



on four, and several of the other seven were exceptionally fine. On 

 the other hand, fine weather was definitely foretold for four days, 

 and on three of these it was experienced. For the rest the predic- 

 tions were delightfully indefinite, but generally managed to steer 

 clear of accuracy. Thus : — 



Ftyrecasi. Ohxerved. 



Feb. 2. Fair to unsettled Heavy rain all day. 



,, 15. Showery to fair Bright and sunny. 



„ IG. Fair to cloudy and unsettled Very bright and fine. 



„ 2i. Fair to unsettled and showery ... Very bright and fine. 

 Of course, one month is too short a time to afford ground for 

 general conclusions, but taking these observations in conjunction 

 with others made casually at various times within the past few 

 years, I incline strongly to Mr. Williams' opinion, that the wind 

 prophecies are, on the whole, reliable, but that the rest are utterly 

 valueless. After all, however, a foreknowledge of the wind, and 

 especially of heavy gales, is the most important thing for practical 

 purjioses, and this is just where the office renders greatest service. 

 Surely, if warning can be given of seven g.ales out of evei-y ten in 

 time to prevent captains from putting out of port, and to saving 

 valuable lives and property, the existence of the Meteorological 

 Department is amply justified. 



Permit me, in conclusion, to wish you every success in your 

 endeavours to disseminate scientific knowledge, and believe me, 



Newcastle-on-Tync, ifarch 3. R. H. Jcde. 



THE WEATHER FORECASTS. 

 [758] — If "Another Observer" (letter 749, p. 153) will turn to 

 " Good Words" for August, 1881, p. 570, he will find the secretary 

 of the Meteorological Department, in a burst of candour, saying : 

 " As regards the possibility of really predicting the weather for 

 these islands, weeks or even days beforehand, it is the duty of all 

 honest meteorologists to warn the public against expecting what is 

 clearly impracticable." This is the bald and literal truth. That the 

 Meteorological Office is a waste of public money may well be con- 

 tended, yet it is fair to the officials to say that they try to do some- 

 thing for their money. No such excuse, however, can be advanced 

 for the so-called " Meteorological Council of the Royal Society," a 

 body which annually picks the public pocket of £1,000, and whose 

 sole raison d'Hre is the private pecuniary benefit of certain " guinea- 

 pig" F.R.S.'s who are not ashamed to receive national money under 

 false pretences. A Thikd 0bsek\-er. 



MULTIPLICATION— MOON'S VERTEX. 

 [759] — Recently I was told of a dodge for multiplying together 

 numbers between 12 and 20. The idea may be new to some of 

 your readers — as it was to me. Take the sum of one quantity and 

 the last digit of the other, and underneath it in imagination, but 

 one place to the right, put the product of the two last digits of the 

 number. For instance : — 



16x17 16 + 7 = 23 

 6x7= 42 



272 

 14x10 14 + = 23 

 4x9= 36 



266 

 There is no difficulty whatever in doing this mentally. I often 

 find it convenient. The reason will be obvious when we consider 

 that— 



(10 + a) (lO + b) = 10 (10 + a + })) + ab 



Your direction, on page 11, for finding vertex by great circle 

 passing through observer's zenith has rather puzzled me. The 

 vertex so found would vary with observer's longitude, and the angles 

 of jjosition would correspondingly vary — so it seems to me. I 

 have wondered whether you did not intend to say the great circle 

 through the pole, but have seen no correction. 



FREn. C. Green. 



[Mr. Green should have addressed his secund remark to 

 " F. R. A. S.,"nottome. I am a Fellow of the R.iyal Astronomical 

 Society, though I have long since ceased to attend meetings; but 

 lam not (Jie "F.R.A.S." who has so long written in the English 

 Mechanic, and in Knowledge since it started. — R. P.] 



A CLEAR THAME.S : 



[760] — Can you give any reason for tlu- unu.^ual transparency of 

 the river Thames? It is a beautiful onun-ald green even so low 

 down as the Temple Embankment, and the snow-white foam which 



