Nov. 30, 1883.] 



♦ KNOWLEDGE * 



300 



two or three pieces of cork between the neck ot the pickle-bottle 

 aiirl the flask, 8o as to allow the air to pass freely. If this be not 

 ziiinded the water will keep its old level always. 



LARGE ■. SMALL WHEELS. 

 [1032]— In letter 985, p. 277, a correspondent (W. W. D.) states 

 that diminishing the diameter of the wheels, supposing the height 

 t(i remain the same, will increase the liability of the tricycle to 

 <ivertum. Surely this is a mistake. The liability to overturn 

 depends (if the height of the seat remain constant) not on the 

 hci;.'ht of the wheels, but on the distance between them. 



A. M. B. 



DULL HEARING AND THE MICROPHONE. 



[1033] — Is there any adaptation of the microphone or other 

 instrument which will gather and convey sound to persons slightly 

 <lull of hearing, for use at public lectures, or meetings, and in the 

 social or family circle, but not in the nature of ear-trumpets or 

 tubes with mouth and ear-pieces of large size, and which are 

 <langerous if used in a crowd ? 



If a sound receiver, fixed say in the breast opening of the vest, 

 could be connected with a microphone, the sound being increased 

 in volume passing through, c<innecting again by wire or thin gutta- 

 percha or indiarubber tubing, with one or both openings of the ear, 

 this would be a boon to thousands who, from thickened drums, or 

 displacement of the small bones of the inner ear, or other slight 

 disarrangement, are just too dull of hearing to catch sounds 

 uttered iu ordinary conversational tone. If this is possible, a 

 small saucer-shaped receiver might be placed on the chest, the 

 microphone being in an inside coat-pocket, the connection from 

 receiver to microphone passing through the arm-hole of vest, wire 

 <ir tubing again connecting with the microphone, conveying the 

 sound, increased in volume, to the ear. The connections could 

 readily be run between the clothing, and passing between the neck- 

 band of the shirt and a buttoned-on collar, be almost or quite out 

 of sight. The sound conveyers to the ears could be easily kept 

 in place by thin spring wire passing at the back of the head, as 

 often used to secure spectacles. 



Te Wiiiti, New Zexi.\kd. 



LETTERS RECEIVED AND SHORT ANSWERS. 

 J. C. P. The "Universe of Stars" is a more scientific work 

 than anj- of the others you name ; " Other Worlds " the more com- 

 plete of the rest, — which treat of general subjects. An atmosphere 

 not necessary for light ; rays falling on any substance make it 

 visible. — F. S. L. Thanks for explanation ; but fear readers would 

 say they knew.— A. C. Rodgkks. Nay, I simply defended Professor 

 Fiske, Vega, and the rest from the tide of your contempt, and 

 .showed what might be said on their side, — I may say on our side 

 Or rather wo are in the mnlst, not on eitlier side : in the midst of 

 darkness visible (symbolization, again, my dear sir). On one .side 

 are those who think they know what God is and wills, on the other 

 side those who think and say they know that there is no God that is 

 and wills ; in the midst are they who feel there is a Power at the 

 back of all we know, but do not pretend to know its nature, 

 plans, or purposes. Your dogmatic denials are as outside our plan 

 MS dogmatic asseriions of belief. For the rest you find indignation 

 and wrath in sentences free from either. You had expressed con- 

 tempt and rancour for us who take the middle track, but wo had 

 and have no rancour or contempt for you on one side, or for the 

 other Gnostics who are over the way. We simply doubt whether 

 you know all you think you know. — F.W. W. My r/mr sir, how 

 could I possibly answer yo.ir question without considering first all 

 discoveries made with the microscope (say ten thick vols. imp. 8vo), 

 then all those made with the telescope (say same space), and then 

 entering on a careful comparison — say ten vols, more, and three 

 lifetimes. 1 would be glad to do this if I could spare the time and 

 possessed the requisite skill : but as matters are I must decline. 

 To fully deal with the u-^c of the microscope to botanist (2 vols.) 

 anatomist (3 vols.), and ;.iliysiologist (3 vols.) would take less time 

 and space; but even for that these columns are not quite largo 

 enough.— D. Alas yes, the man in tlie moon is inverted in the 

 Houthorn hemisphere ; but percimtni the telescope which inverts him 

 hero puts him right side up there. — J. K. V. Thanks.- Pektimhiich. 

 You have no reason to be perturbed by Professor Cayley's address 

 and the idea of a fourth dimension in space. Would the idea dis- 

 turb you that as yet we cannot conceive the square root of a leg of 

 mutton? — H. J. W. Do not know the names you mention; but 

 know that very good instruments of moderate price often so pro- 

 curable. — -W. Fraser. Fear can give no satisfactory opinion about 

 the suggested motive power of tricycles. — Tmokol'gh. I agree with 



you as to the desirability of stamping out inherited and inheritable 

 tendencies to crime, if it could be done ; but not by execution. 

 Why not simplj- remove from their fellow-men ? — More Light. I 

 have no chance of investigating the system just now. — J. Ei'Wabds. 

 Thanks ; but meteor you saw not unusual, and your observation 

 gives no evidence available for determining its real path in our air. 

 — R. P. J. The subject of poker across fire was fully considered 

 long ago. I can find no possible scientific reason for it ; and 

 it is well known it began by way of making the "sign of 

 the Cross " over the fire. Sunlight seems so obviously to 

 dull firelight that the mistake in that case is natural enough. 

 — M. G. I do not myself think the sun will ever be an abode [of 

 life. Saturn very obviously visible to the naked eye just now near 

 Aldebaran, — being brighter than that first magnitude star. — 

 W. C. M. Thanks for clever and amusing lines. Would print them 

 here if I dared. But a host of misunderstanding ones would fall on 

 me forthwith. — H. B. Heath. If two persons leave Greenmch at 

 noon exactly, on Monday, one east the other west, and travelling as 

 quickly as thought reach longitude 180° from Greenwich, one can 

 draw no distinction between the day for each. At noon in latitude 

 0°, Monday is just beginning at a point a hair's breadth west of 

 longitude 180°, and just ending at a point a hair's breadth east of 

 that longitude. But at that precise longitude you can say neither 

 one thing nor the other. If a traveller having gone west in an 

 instant to a point just short of 180° were then to take a step 

 over that longitude, he would theoretically pass from the begin- 

 ning of Monday to the end of Monday or the beginning of Tuesday, 

 but a step back would take him to the beginning of Monday again. 

 M'cHESTEE. I regret that I have no personal acquaintance with 

 Dr. S. — R. A. Law. Thanks. The Boston yellow sun was com- 

 mented on iu these columns, I think. — W. H. Spencer. Thanks for 

 picture showing seven sun.spots visible March 30, 1870, to the naked 

 eye (separately visible, if I understand you aright). — Merlin notes 

 that two suiispots were visible to the naked eye on July 21 last. — 

 H. K. H-UiRis. The auroral gleam often extends as far as due west, 

 and its centre is always considerably to the west of north. — C. H. J. 

 We could not just now find room for the suggested botanical papers. 

 — J. DVER shows convincingly that the flat earth theory would 

 necessitate two days and two nights, each about six hours long, in 

 every twenty-four hours. — H. Rolfe. Certainly more people have 

 died within the last 800 years than are living now. — H. C. Standage. 

 Can recognise no such claim, the MS. having been sent unasked. — 

 Albion. Laws of spelling inscrutable. As you say, why should 

 some of those words be spelled with e, some without ? They would 

 all be spelled with e's if we had a constant rule. — C. A. Ede. Many 

 thanks. — J. C. Kernshaw. Thanks, but that was not a lunar rain- 

 bow, though rainbow colours were shown. A lunar rainbow can no 

 more encircle the moon, than an ordinary rainbow can encircle the 

 sun. — Jas. Browx. The air too thin to be warmed appreciably. — 

 H. Seward. The paragraph and paradox simple bosh, as you suggest. 

 — Michael Mtrphv. Arrah, be aisy. 



O^ur WlMnit Column, 



By " Five op Oldbs." 



Whist Ending p. 311. Correct solutions of both 1 and 2 by 

 J. H. D. L., K. R. M., Long Tramp, Bumper, J. N. Harrogate, and 

 M. Wilson. Solutions of 2 by C. N. W., No Whist Player, (Sad) ! 

 A. M. Chambers, R. Carthwaite, J. Hargrade, M. PenHington, 

 Veritas, Crafty One, J. N. Mumbles, K. K., and L. J. N., correct. 



Several correspondents answer 1, which is really the easier ques- 

 tion, incorrectly, though solWng 2 correctly. Of course, to win, Z 

 must lead the long Spade ; but if A trumps and V overtrumps, or if 

 A throws a Club and Y trumps, A 1> can win every trick if they 

 play correctly. A. M. Chambers, M. Pennington, and others make 

 A throw a Club, Y trumps and B overtrumps ; then /> leads a Club 

 and A, winning the trick, leads a Club. This would be throwing the 

 game away. If A load a trump through Y's minor tenace, B ivins 

 all the remaining tricks. Y can only win by throwing his Club to 

 Z's lead of the long Spade. Ho can only then be led through once, 

 whereas for .4 B to win every trick Y must be led through twice, 

 since he holds 2nd, -Uh, and Gth best trumps. 



Next week the game closing with this pretty position will be given 

 in full. 



J. W. — Y'es : a player is entitled to look at the last trick at any 

 timo during the play of the current trick. The idea that ho cannot 

 do so until all four cards have been played, though sometimes sug- 

 gested, is quite mistaken. The last trick is looked at (but by in- 

 attention of players only) to guide the play in the current trick : 

 at least this is so in nine cases out of ten. 



