4i6 



♦ KNOWLEDGE ♦ 



[Mat 22, 1885. 



" entering bar first quarter," is simply applied to the arrival of the 

 moon at that part of her orbit in which she is dichotomised, and 

 is not intended to imply that she is beginning the first fourth part 

 of that orbit. I note your desire that the attention of Mr. Mattieu 

 Williams should be called to your communication on p. 324 of 

 Vol. YI.— C. M. IIarbokd. Gould's books " Birds of Asia," " Birds 

 of Australia," "Birds of Europe," " Birds of Great Britain," " Cen- 

 tury of Birds from the Himalaya Mountains," " Humming Birds," 

 ic, will afford you a vast amount of information. They must be 

 sought in some public library, like that of the British Museum. 

 There is a gigantic American Ornithological work, too, whose 

 title I have forgotten. The ornithology of Africa has, so 

 far as I am aware, never been treated of as a whole. 

 — H. Trl'eman Wood. Received with thanks. — Augustus 

 J. Harvey suggests tho establishment of a National Pho- 

 netic Training College for Great Britain. — W. H. G. The 

 puzzle of M. T. H. (letter 1701, p. lul) is not, as I understand it, 

 as to the manner in wliich the rays of light are reflected from a 

 mirror, but whether in the absence of a percipient eye there is 

 any reflection at all ? — H. R. B. Do you — or, in fact, does the 

 Duke of Argyll — sufficiently distinguish between the inconceivable 

 and the unbelievable ? The King of Siam, who refused to credit 

 the fact of the existence of ice, which was described to him by the 

 Dutch travellers, did so on the ground that it was inconceivable. 

 Had he, however, chosen (or rather been in a position) to investi- 

 gate the matter scientifically, he might have satisfied himself of the 

 possibility — nay, of the feasibility — of the solidification of water. 

 That, however, 2x2 = 5, or that the three angles of a plane 

 triangle can together be less than two right angles is absolutely 

 unbelievable. Moreover, your illustration from mind and matter 

 is a purely personal one. Dr. Lewins, Miss Naden, F. W. H., 

 and others would tell you that no proof exists in the slightest 

 degree of the action of mind (as a separate entity) on 

 matter. — M. Gordon Munro. Your letter shall appear. — 

 W. H. Jones. Inasmuch as the " Mind and Brain" discus- 

 sion was drifting more and more rapidly in a merely theo- 

 logical direction, you will see that I have been compelled to stop it. 

 — J. Maccai.lan. Scarcely a matter that I could " clear up " in a 

 " line or two " — or a page or two either. See " Other Worlds than 

 Ours," " The Borderland of Science," and "Science Byways," by 

 the Conductor of this journal. — M. A. I have assuredly never 

 heard of any one having offered a reward for the formation of 

 magic squares of numbers of the form 4 m + 2. Do any of our 

 readers know of such an offer ? — C. Caldicott sends (in connection 

 with letter 1C55, p. 289) a letter written by a lad between 12 and 

 13,_ whom he (Mr. Caldicott) has taught to' write with his left hand. 

 It is certainly an excellent specimen of caligraphy — bold, legible, 

 and very superior to nine-tenths of the " right-handed " writing 

 one meets with every day. — W. G. Howard. " You may as well 

 kill a man," says an old proverb, " as frighten him to death." 

 That the suggested Channel Tunnel may (or may not) be one of 

 the greatest blessings that could be conferred upon England and 

 France, and that the panics which would periodically arise might 

 (or might not) be senseless, undignified, and short-sighted, are 

 matters on which a diametrical difference of opinion may legiti- 

 mately exist. Just so long as human nature is wh.at it is, however, 

 and the lamb, when he lies down with the lion, lies down (as the 

 American observed) " inside him," I cannot conceive that any 

 Government would be justified in subjecting the nation to the huge 

 cost of periodical panics, be they ever so foolish or unfounded. — 

 Thebeeton. Kindly read the reply to Mr. J. W. Frazer on p. 75.— 

 >v . Cave Thomas. I am in some difficulty with reference to your 

 lecture on " The Bases of a Science of ^'Esthetics," inasmuch as 

 it IS far too long for reproduction in tho present overcrowded 

 state of our columns, and to summarise it as a contention that " a 

 science of aesthetics must consist in rightly-formulated principles 

 of proportion," is to do you but scant justice. — J. Murray. In 

 the classical words of the clown in the Christmas pantomime, 

 " Here we are again !" I have read through your communication, 

 but (as the senior wrangler said upon the perusal of " Paradise 

 Lost ") " It doesn't seem to me to prove anything." With reference 

 to your allegation that " As our earth diminish's the sun declines, 

 just as I said twelve months ago," I can only observe that, unless 

 your verbose statements of a preposterous hypothesis diminish, f 

 must decline (to further notice them), as I said six months ago. — 

 Mi.'i.s M. B. Alder. Many thanks. Forgive me if your arguments 

 fail to convince me. — Captain Nholl.s, K.N. Thanks; but we 

 have such a redundancy of matter in hand, that I could only accept 

 it as a voluntary contribution. — Dr. Baexardo. Thanks, but it is 

 quite outside of the province of a journal devoted to science. — 

 John Stanton. The specific gravity of ice is 0'9184 (that of water 

 being, of course, I'OOO.) In the act of freezing water expands 

 very considerably, so that 174 volumes of water at 60 Fahr. 

 become 184 volumes of ice. Water, like the vast proportion of 



bodies, goes on contracting until it reaches a temperature of 

 39 Fahr., at which it is at its maximum density. Then it begins 

 to expand, and continues to do so, as I have just said, until, 

 becoming ice, its expansion is very considerable. Bismuth acts in 

 a somewhat similar fashion. — T. C. ToWNSHEND. I know nothing 

 of Mr. Morrell's address, but have forwarded your card to the 

 office in case any one there may be acquainted with it. If 

 tradesmen will not advertise their addresses I must certainly 

 decline to act as intermediary between them and their in- 

 tending customers. — Eichd. Jarman asks for the meaning of 

 " Fan Structure" as a geological term. It was asked, he says, at 

 the last South Kensington Science Examination. Myself a practical 

 geologist, and familiar with every standard work on the subject, 

 the phrase is new to me. Doubtless it is to be found in one of the 

 wretched cram books compiled by some official of the " Depart- 

 ment." — Howard Grauame. The dynamics of a spinning-top would 

 rather require a series of articles for its explauation than admit of 

 being made plain in an answer in this column. Have you never 

 heard that Euler wrote an entire volume De motu turhinis ? Y''ou 

 may go on teaching the wave theory of light in absolute disregard 

 of Sir W. Thomson's reported utterances. The (comparatively) 

 trivial difficulties to which he adverted will all bo removed in due 

 time. Do 3'ou not remember that, prior to the discovery of Nep- 

 tune, it was gravely alleged that the law of gravitation broke 

 down at Uranus ? Yes, in any given medium the red does travel 

 faster than the violet. 'The word "cloud" should be, as you say, 

 "closed." "Pane" is quite right. I am not quite sure what 

 " Hallyards " meant in the words you quote. Speaking generally, 

 of course the greatest heat is to be found at the least refrangible 

 end of the spectrum. I really cannot explain to a third person a 

 reply to a communication addressed to me by a second, in connec- 

 tion with which it is quite intelligible. — W. K. Bradg.^te. Un- 

 doubtedly, as the sentence stands, Humboldt (who was no more 

 infallible than any one else) made a mistake. I suspect, though, 

 that he must have meant that the comet was only visible in a tele- 

 scope at the time of its discovery by Pons, and that he inadvertently 

 omitted to qualify his statement as to its invisibility. — Lawrence 

 Hargeave. Model of your trochoided plane flying-machine re- 

 ceived. As far as I have experimented with it, it exhibits an unfor- 

 tunate tendency to pitch straight down to the ground, on one end. — 

 Excelsior. Your difficulty having been cleared up, 1 really cannot 

 continue to forward such bolsters of MS. as those which reached 

 me to-day. The proper motion of the earth is invariably taken 

 into account in estimating the rate of appreach or recession of a 

 fixed star from the change in its spectrum. Before framing hypo- 

 theses and dogmatising on such a question as this, it might be 

 expedient to make yourself acquainted with the literatm-e of the 

 subject. — G. L. Brown points out that, in his letter (1704) on 

 p. 420, "o Cancri" should have been n- Cancri. — E. W. P. I see, 

 and to a certain extent sympathise with the drift of your remarks. 

 The cases, liowever, are not strictly parallel. All telescopes are 

 identical in construction ; and to mention tho name of individual 

 makers of them is really and truly to advertise particular tradesmen. 

 In the case of tricycles, the various forms described by our contributor 

 differ inter se. Hence, in saying that Smith's Lightning Express is a 

 better form of machine than Jones's Hurricane Kear-steerer, he is, 

 in reality, only giving utterance to something equivalent to the 

 assertion that for showing planetary detail, itc, a reflecting tele- 

 scope surpasses a refractor of the same price. All the same, I 

 should be glad for the trade-element to be kept as much as possible 

 out of the articles on which you comment. I differ with you 

 entirely on the subject of the " Young Electrician" articles, which 

 are intended to instruct the student in making his own electrical 

 apparatus. Surely this is applied science " plainl}' worded — 

 exactly described." As to the Workshop essays, they are written 

 as supplying a pleasant means of recreation. We in no sense 

 whatever enter into competition with the journal to wliich you 

 refer. I am obliged to you for your intimation of the opinions of 

 yourself and your friend ; but must, at the same time, assure you 

 that they differ, toio cwlo, from those of other correspondents. I 

 have given up, as an utterly hopeless task, the attempt to please 

 everybody, and have taken to heart the moral of the fable of the 

 Old Man and his Ass. — Divers Correspondents, from whom some 

 quires of MSS. have accumulated, are once more requested to note 

 that 1 neither can nor will return rejected contributions unless 

 they are accompanied by envelopes legibly addressed and suffi- 

 ciently stamped. Furthermore, I must ask them kindly to note 

 that I must claim absolute power to reject any communication, 

 without assigning reasons for so doing ; and that I utterly refuse 

 to enter into correspondence with the authors of papers which I 

 regard as unsuitable for the columns of Knowledge, to argue as to 

 their contents, or to justify any action which I may see fit to take 

 with reference to them. — E. L. G. Many thanks ; delighted to see 

 your handwriting again. 



