Feb. M, 1882.] 



KNOWLEDGE 



363 



siilorable show of reason, and adduces some striking facts in sup- 

 |i(jrt of them. 



Ueintr myself a mere sciolist in geolog)-, or, indeed, on any scien- 



ill,. ~"l.j>ct, I can offer no opinion as to the validity of his reasoning 



1, but I am anxious to know whether any of your readers 



■ with the work, and how far it is considered worth atten- 



. ;; 1. , English scientitic men. B. 



Edinburgh, Jan., 1882. 



HOG PUZZLE. 



[288] — Here is a new hog puzzle, by Lieut. -Col. W. U. Oakes, of 

 iirithmetical renown. Some of your readers might like to solve it. 

 Vou shall, ne-tt week, have his solution of it, and also one of the 

 original |)nzzle in short and simple arithmetical form. 



Four married couples went to buy hogs. Kach individual bought 

 as many hogs as he or she gave shillings for each hog. Also each 

 husband laid out the same number of guineas more than his wife, 

 and tliis number of guineas was the smallest consistent with the 

 condition that the numbers of hogs purchased by the respective 

 husbands in excess of the numbers purchased by their respective 

 wives form four consecutive terms of an increasing arithmetical 

 series. How much did each husband expend more than his wife ? 

 Herbert Rees PniLiprs. 



PL.\TING— ASTRONOMICAL— CHEMICAL. 



[2S1I] — I have to thank " C. T. B " for his reminder. He might 

 try the solution described, for iron, but I am of oi)inion that he 

 will find the only way for iron to bo with a battery and alkaline 

 solution. But, surely, "Watts' Dictionary" should help him 

 through. 



On page 211, Professor Young says, in effect, that the sun's 

 pull on the earth could only be sustained, or replaced, by a 

 bar of steel many sipiare miles in section. Sir E. Beckett, in 

 " Astronomy without Mathematics," (page 312) tells us : — " The 

 tractive force on a fast railway train of 400 tons, on the level, is 



found to be about four tons But if the eartli were such a 



train, it would e.'sert a centrifugal strain of less than five hundred- 

 weight on the rope which held it to the sun." These two views are 

 opposed to one another, and therefore one must be incorrect. 

 [Pardon me ; the two views are quite consistent with each other. 

 Sir Edmund Beckett says, if the earth were such a train, that is, 

 if her mass were only 'tOO tons. — Ed.] 



Tho account of the mannfacture of gas from wood, page 246, 

 also requires elucidation. Carbon monoxide is rather " com- 

 bustible " than supporting combustion. The finished article is said 

 to be free from " dangerous, obnoxious, and otherivise objectionable 

 products." It would be better worth while to caution one against 

 the exceedingly poisonous properties of this gas : besides which, 

 coal gas is harndess. Unlike the case of carbon dioxide (which is 

 not poisonous, and which has an odour, whatever our text-books 

 may copy one into another), fresh air does not revive one from 

 suffocation by carbon monoxide. This gas, as is well known, bums 

 with a pale-blue flame (the blue flame often seen over a sluggish fire 

 is CO) of feeble luminosity. How, then, can it confer on "an 

 inferior coal gas " a " great candle power .' " Lastly, tho CO.i 

 takes up carbon, from the heated charcoal according to the 

 equation — 



C0; + C=2C0, 



80 that eventually the charcoal disappears, except an ashy residue. 

 Where, then, is the danger of " too great an accumulation of 

 charcoal ? " and why withdraw from the retort the substance that 

 is also put into it ? Lewis Aruxpel. 



[The account was not quite clearly written. It seemed obvious, 

 however, that P.C.S. referred to wood gas itself, when burning in 

 the usual way, as innocuous, not to carbonic oxide. — Ed.] 



ELECTRO-PLATING. 



[290] — Letter 119 has evidently escaped the notice of your 

 readers. If I were W. Vaneys, I should throw down the Cu from 

 the solution by meuns of the battciy. Cu m an Ag solution, being 

 thrown down before the Ag. He will understand me, without my 

 taking up any more of your valuable space. F.C.S. 



HORSERADISH— INTELLIGENCE OF A CAT— SCENT— 

 " KNOWLEDGE." 



[291] — With respect to horseradish, Mr. Henerman must know 

 that it, in common with garlic (Allium ursinum and A. satirum), 

 onion, leek, eschalot, Ac, yields on distiUation a fetid-smelling com- 



pound oil called allyle, from the genus that it characterises. The 

 astringency of mustard and horseradish (probably also cress, 

 radish, and such like) is due to sulphuret of allyle in combination 

 with cyanogen, I mention the fact that there are other plants 

 having those properties which we value in horseradish to remind 

 Mr. Henerman of tho extraordinary proclivity of all nations to use 

 them as condiments. I cannot call to mind ,a single nation that 

 rejects them ; in fact, some people will not bo satisfied with any- 

 thing weaker than /eru/a as.sii/ffifida. I do not suppose that horse- 

 radish "acts" in any way upon the stomach, although so general a 

 use betokens some effect beneficial, or at least pleasing, to the 

 system. While " warming " the appetite, and, as a condiment, 

 grateful to the taste, it probably has no undesirable effect. 



There lives, near where 1 write, a cat that can -without fail open 

 tho back-door by siiringing from the ground to| the latch-handle, 

 and, while holding with one paw, can raise the latch with the 

 other, finally swinging the door forward by means of a push 

 with the hind leg. We might almost expect, as a last step to 

 so great reason, a certain amount of culture. But tho house- 

 wife complains that, having taught itself, to gain its own end, 

 admission, it will not consider further, and close the door again. 



" Prestcr W." himself states about all that is kno\vn of the 

 nature of a scent (No. 11, query 170). It is questionable, how- 

 ever, that he is able to recognise a perceptible decrease of weight 

 in scent-giving substances. I was under the impression tliat there 

 was no measurable decrease in weight, but having paid iio attention 

 to the subject I await a correction. Dr. Carpenter (in "Com- 

 parative Physiology") remarks that "a grain of musk has been 

 kept freely exposed to the air of a room, of which the door and 

 wiudows were constantly open, for a period of ten years, during all 

 which time the air, though constantly changed, was completely 

 impregnated with tho odour of musk ; and at tho end of that time 

 the particle was not found to have sensibly diminished in weight." 

 Here is an illustration of the extreme minuteness of a molecule ! 



I express my regret, sir, that you (whose leadership my " set," 

 at least, fully trust) should have been thus far so troubled with 

 Dugaestions. Knowledge assuredly needs no such small patronising 

 ways, and judgiug from its rapid spread in this district, it will be 

 the magazine of the future of its sort. Connerhugel. 



THE WEATHER OF JANUARY 12-24, 1882. 



[292] — Some notes on the weather in tho South of Ireland during 

 the past exceptionally mild month may be interesting, as enabling 

 your readers to make comparisons with the weather of more 

 northern and eastern districts. It is not common to observe in 

 winter a high barometer and a high thermometer together, but we 

 have here observed a remarkably high mean of both instruments 

 during a considerable part of the period. During the fortnight 

 Jan. ll-24th, the mean height of the barometer reduced to 32°, and 

 mean sea-level was 30-5 in. The mean of maximum thermometer, 

 was 51*7° of minimum, 43"6°, mean for fortnight, 47'65°. The mean 

 daily temperature was 50° or above, on the 11th, 12th, 13th, 14th, 

 15th, and 16th, and fell short of it by about half a degree on the- 

 23rd and 24th. The highest temperature in tho sun was 80° {not 

 by a black bulb in vacuo) on the 24th. The .iverage daily tempera- 

 ture for the above-mentioned fortnight (mean of 50 years at Green- 

 wich), is 30-3', showing the prodigious excess of 11-35° above the 

 mean this year. 



As might be expected, the effect upon vegetation has been 

 striking. On Ross Island, Killarney, horse-chestnut had opened, 

 and several boughs in full leaf were gathered Jan. 22. On that 

 date the following plants had been found in flower, tho first-named 

 three or four having been in bloom a fortnight : — 

 Ulex spinosa Prunus spinosa (once) 



Senecis vulgaris Nepeta glechonea 



BeUis peronnis Crocus (yeUow) 



Veronica hederofolia Galanthus nivalis 



Capsella bursa-pastoris Potentilla fragariastrum 



Viola tricolor Lanristinus 



Lamium intermedium Laurel (coming in flower) 



Leontodon taraxacum Primula vulgaris (beginning of 



Erauthus hyemalis month) 



Petasites vulgaris Poa annua 



Ranunculus ficaria Veronica chamasdrys 



,, repens (once) Cardamino hirsuta 



Coryllus avellana 



No rain has been registered between the 15th and 25th. The mean 

 force of wind has been only 1'7. During tho height of the anti- 

 cyclone (when for three days the barometer stood above 30" 7 in.), 

 the sky was thickly covered with stradus cloud. Sunshine accom- 

 panied the reduction of pressure. On the 18th tho barometer 

 reached 30° 94 in. G. R. Wynnk, F.M.S. 



