138 



KNOWLEDGE 



[Fib. 13, l&fcS. 



rialism," ]ie ppcaks still more strongly : " The passage from tlie 

 physics of the brain to the corresponding facts of consciousness 

 is unthinkable. Were our minds and senses so expanded, 

 strengthened, and illuminated as to enable us to see and feel 

 the very molecules of the brain ; were wo capable of fuUow- 

 ing all their motions, all their groupings, all their electric 

 discharges, if such there be ; and were we intimately acquainted 

 with the corresponding states of thought and feeling, we should be 

 as far as ever from the solution of the problem, ' How are these 

 physical processes connected with the facts of consciousness 'i ' " 



I am still quite unalilo to discover that I have a consciousness 

 of "unconsciously " liking tilings. Tlie verb "like" implies con- 

 sciousness. If I say that I like mutton, I mean that this par- 

 ticular kiud of meat produces a certain definite, molecular 

 arrangement in my brain, which is the physical fact somehow 

 connected with the pleasant sensation of which I am conscious. 



J. T. EOUTLEDGE. 



FRICTION. 

 [1592] — I am surprised to notice Mr. Browning, in his article, 

 "How to Take Care of a Tricycle," in No. 170, state that "fricticm 

 increases u-ilh relocilij, Ivt 7wt with pressure, unless the pressure is 

 so great that the lubricant is squeezed out." It is only necessary 

 to look up any authority on mechanics to find that " the resistance 

 due to friction is equal to the direct pressure between the surfaces 

 multiplied by the co-efficient of friction, this co-eiEcient depending 

 on the nature of the surfaces and the lubricant adopted. Of course, 

 the latter part of Mr. Browning's statement quoted above is correct 

 in so far that friction greatly increases when the pressure is so 

 great as to force out the lubricant. J. Y. 



LETTERS RECEIVED AND SHORT ANSWERS. 

 S. L. B. points out that (according to the text) tho words 

 "Perihelion" and "Aphelion" are transposed in the diagram on 

 p. 80. — Nemo. I am sorry to find you wasting your time over such 

 trash as the printed letter you enclose. The person who wrote the 

 paragraph concerning the satellites of Uranus was hopelessly igno- 

 rant of astronomy. The motion of the satellites of Uranus, as 

 i-eferred to those of every other satellite in the solar system, is 

 retrograde— unless you choose to say that the plane of their orbits 

 has not only been rendered perpendicular to the ecliptic, but has 

 been tipped 10° over towards the other side ! I suspect that the 

 (so-called) " medium " got her knowledge of the two>atellites of 

 Mars from " Gulliver's Travels," whence we learn that they 

 were discovered by the astronomers of Laputa (see paragraph nine 

 of Chapter III. of the " Voyage to Laputa," in " Gulliver's 

 Travels;" and remember that this was written in 1727). Pray 

 read paragraph in capital letters which concludes the head- 

 ing of the CoiTCspondence column. — Wm. Dotx.L.is. Simpkin, 

 Marshall, & Co., London, publish the book you want. — 

 A. J.^ W. The discs which your telescope gives to stars are merely 

 spurious or optical ones, the star being in reality a point of light of 

 absolutely insensible dimensions as viewed from the earth. Your 

 notion, then, that its circular figure (which is the product of your 

 object-glass, and of that alone) would undergo change were an 

 opaque body gradually to intervene, is perfectly baseless. Oh, yes, 

 the interposition of rings of planetoids, meteorites, or nebulous 

 matter has been suggested as a cause of stellar variability. In the 

 case of stars of the Algol ty]ie, their periodical partial eclipse by a 

 huge dark satellite seems to afford the most feasible explanation of 

 their variation. — E. A. Tixdall. Your football experience so 

 strongly resembles that of C. (letter 1570, p. U-l) as to be scarcely 

 worthy of reproduction. Forgive me for saying that every one who 

 writes to this paper is entitled to have his communication acknow- 

 ledged ; and to leave people without replies simply because they 

 make foolish or unjustifiable requests would be to invito a repetition 

 of letters which they would then believe I had never received. I 

 have excluded, and shall continue to exclude, all theology, properly 

 so called. Certainly Dr. Lewins's letter in no sense trenched upon 

 this ground, although "An Earnest Thinker's," I fear rather did. 

 However, the last-named correspondent will have to modify his style 

 of argument (?) if he again seeks admission into these columns. 

 The papers on "Light-sifting" will appear when others now in 

 hand are disposed of. It occurs to me (rightly or wrongly) that 

 you must be a very young man, if I may judge from the calm affec- 

 tation of infallibility with which you are so good as to try to teach 

 me my editorial duties.— P.\trick O'Brien relates how he dreamed 

 that a favourite cat was sitting at the foot of his bed, and, after 

 awakening, distinctly saw the dream-image of the cat for several 

 seconds. This persistence of objects seen in dreams on rousing 

 is not a very infrequent phenomenon. Thanks for your P.S.— 

 London and Westmin.ster Supply A.ssochtion. Received, — J. M. 

 A moment's reflection will show you that your letter amounts to a 



mere advertisement of a particular tradesman. This can only 

 appear in the proper columns. — A. If a man did not habitually 

 dress for dinner every night, I can fpiite understand how the 

 taking off his clothes would suggest the act of winding-up his 

 watch. It is only when we reflect a little that we realise how 

 many of our actions are automatic. — F. Gaktside-Tippinge. 

 Snch communications should be directed to Richard Hodg- 

 son, Esq., St. John's College, Cambridge. The Society's 

 address is 14, Dean's - yard, Westminster, London, S.W. — 

 Night Student asks for the simplest and cheapest form of artificial 

 light for painting by. Pending replies from experts, I should say 

 that a Duplex lamp, with a neutral-tint chimney, would be as efii- 

 cient as anything. — W. R. Bland writes that SIcssrs. Newtons and 

 Messrs. Negretti & Zambra, London opticians, sell the anorthoscope. 

 Prices not given, as this is not the part of the paper in which 

 advertisements appear. — R. Elmore. Pre-occupied as I am, it ia 

 simply impossible for me to make engagements to personally view 

 pictures, apparatus, exhibitions — or, in fact, anything else. — F. W. 

 Rudler. Received with thanks. — Boyd Mo.ss. Do yon not see 

 that you are simply asking me to advertise a particular trades- 

 man gratis? — Leonard Okrell Hey. A superstition, and an 

 utterly baseless one, of which it is difficult to trace the origin. — J. 

 Newman asks Mr. Mattien Williams how to prevent the formation 

 of "mother" in cider that is being made into vinegar. — John 

 GoRHAM. Subject to limitations of space, I shall be pleased to 

 insert your paper. — Caroline A. Martineau. Many thanks for the 

 trouble yon have taken, but j'ou will perceive that I have had 

 to condense your condensation very materially indeed. It 

 would be impossible to give anything approaching to ver- 

 batim reports of popular lectures on subjects alreaoy so fully 

 treated of as that is in the works of Darwin, Lubbock, &c. — 

 G.H.Wilkinson suggests that Mr. Alexander (letter 1575, p. 95) 

 cannot have been " unconscious " if he talked " reasonably ; " and, 

 further, that temporary concussion and chronic disease of the brain 

 affect it differently. Double vision in drunkenness has its origin in 

 the abnormal condition of the circulation in the brain, which renders 

 it impossible for the subject to co-ordinate the movements of the 

 muscles of his two eyes. For single vision the object must be 

 presented to both eyes under precisely similar conditions. — R. 

 Abaerelton. Received. According to your idea, the critic must 

 have misinterpreted the internal evidence. Tho conductor of this 

 magazine signs every line he writes in its columns. — Threepence. 

 I could easily give you another couple of pages, were I to print 

 more of the letters which reach me ; but, as it is, can you give me 

 the name of a single scientific journal in which you obtain the same 

 amount of oriiiinnl matter for your money? — Wm. SwAN.^iTON. 

 Received. — Captain D. Forbes. Thanks; but the alterations 

 are merely of professional interest, and are not sufficiently great 

 to justify the occupancy of space with them. — G. D. D. 

 Your use of the word " equilibrium " is not legitimate. — 

 The force of gravity is acting on the body from the very instant 

 that it leaves the hand ; and continues to act against the projectile 

 force until it nullifies and overcomes it. — ZoiLUS. The language is 

 neither mine nor that of any contributor to these columns. In 

 reproducing articles of interest, as is occasionally done, they are, 

 and only can be, reprinted verbatim. — Geometres. I regret that I 

 have no room at my disposal for papers on elementary arithmetical 

 and geometrical teaching. Knowledge was not established as an 

 organ of primary elementary education. Your supposed solution 

 of the problem of the trisection of an angle by Euclidean geometry 

 is returned to you by post, as at once unsound and unsuitable. 

 Kindly note that I neither can nor will enter into any discussion 

 whatever with you on the subject. — H. B. L. " A hundred snns" 

 was merely " fa(^on de parler." I question if any one has con "fei? 

 more stars in this group than Wolf. — Ada S. Ballin. Received, 

 with thanks. — W. Oldham Chambers. Thanks, will be utilised. — 

 John Ross. Forwarded to the conductor. — Captain D. M. Forsyth, 

 R.N. " Elementary Astronomy," published by Cassell & Co., is, I 

 think, the book you mean. Kindly read the paragraph in capital 

 letters which concludes the heading of the correspondence columns. 

 — Dr. Prevo-st. I have for a long time had a manuscript article 

 lying here. If you wish it returned, kindly send a stamped and 

 directed envelope for that purpose. — W. R. K. calls attention to a 

 truly extraordinary mistake in the engraving of the Star Map on 

 p. C5, where south-west, west, and north-west are printed for south- 

 east, east, and north-east, and Dice versCi. — John Harris. Received. 

 — Clark Bell. Received. 



The circus-ring at the Covent Garden Theatre has been entirely 

 covered by what is probably the largest mat yet made. It is over 

 two tons in weight, and is made of unbleached cocoa-nut fibre, has 

 a soft pile 4 in. thick, and makes a good substitute for turf. 



