482 



• KNOWLEDGE • 



[Maech 31, 1882. 



first kinil, but lui hi* object i» to movo tlin bunt, nml as tlio l>out'fl 

 woight in iirfctxl fnini tlio ruwiuck, llu< ruwluck cannot iwmiibly bo 

 ro)(iir<lc<l nil tbi- fiilrnim ; for tlio fulcnim in ovory Icvor in tho 

 point il'ii/ijiui from wliich tlio woiRliI in liftod. — Kkin. Tho dates 

 and lioum incntinnod boxlilo tho monthly star nmp, mark the timca 

 nt which tho stnm nro in I ho podition shown in tlio map. Tho mnp, 

 of coiinw, can lie mod nt any timo within nn hour or no boforo and 

 after tho tinion niimod. Your nufrtrention noticed ; you will find wo 

 nro not nt nil innttontivo to nii^'^'oHtionH intended to enhance the nso- 

 fulnods of tho mnpii. — (iBAPATiM. Wo know of no (foncml Holutions 

 for Buch problems ns : " Fiinl two conBccntive integers <100, which 

 shall contain no factors other than powers of 2, or 3, or 5." Ac. Such 

 ciue.itions nro scarcely suited for our columns. — K. D. G. Queries about 

 plants in bedroom, scii-ntilic terms, and salt already sullicicntly 

 iinsweroil. — F. J. Stkvkn.son. Wc intend soon having; somi! impcrs 

 on the Arabic unines of stars. — One Not Convimeh. (1.) Have 

 you over tried to bring a plumb-line into line with a star, from a 

 distance of (say) 200 yanls i* You will .find it easier to talk of than 

 to do. (2.) A pio-dish full of water would have rellected Alpha 

 Draconis as well as a boily of water in the pluggcd-np hole ; bo 

 also a passage an inch in diameter would have shown tho 

 star as well as tho four-feet-sqnaro descending passage, — if 

 you chanced to get it in tho right direction. Tho difficulty 

 is to do it. By taking only a small reflecting surface you 

 produce precisely the sanio effect as if you diminished to 

 corresponding degi-eo tho cross-section of the descending passage. 

 With water poured in, ns I have suggested, the ascending passage 

 would bo ef|uivalent optically to the prolongation of the descending 

 one. 3. You " cannot debit such a waste of material as the grand 

 gallery, used for so short a time, to men otherwise so clever as the 

 Pyramid builders." How arc you going to avoid the difficulty ? It 

 applies far more to Smyth's theory. You might have waited till 

 my theory was fully described. The question you asked over 

 name "Uumbenira" has been asked, and, by the way, has not been 

 answered. A spinning peg-top presents many difficulties. — 51. H. C. 

 Thanks ; but that was not what Newcomb meant. He has 

 admitted tho erroneous nature of his explanation. — JAS. Ckain. 

 Thanks for] magic cube ; will put it by in the hope that ere 

 long I may use it. — .Ias. Grit.ndy. Many thanks. — L. W. H. 

 When you look at a landscape in an inverted position (best not in 

 public) a part of the retina receives the image which in tho 

 ordinary attitude is not used and is therefore more sensitive. — 

 Ecliptic. There is no general formula by which magnitude of 

 eclipse and times of beginning and ending for any place can be 

 computed. — W. M. Science cannot yet explain the qualities 

 which the ether of space seems to possess. Bead Uerschel's 

 Essay on Light (Familiar Science Lectures). — W. A. C. Mr. 

 Button does not assert, but admits that were animals not used 

 for food manj' must starve. Ho is intensely humanitarian, 

 some think extravagantly so. Of every class of animals, including 

 man, many times as many arc brought forth as could possibly co- 

 exist. Some musf perish. — D'Abtagcax. It is a matter of opinion. 

 It seems to me unnecessarily confusing to describe same number 

 repeated several times as an arithmetical and also a geometrical 

 series ; and to ask what proportions of gold, silver, and copper, 

 exist in an alloy, when the etpiations show that there is no copper 

 at all. The purpose of examinations is to ascertain what the 

 examined know, not to perplex them.— W. F. See our monthly 

 pa|>er8, beginning mth No. 21. — J. S. V. Paper on the Transit of 

 Venus soon. Have ^vritten no work on Practical Astronomy. 

 — E. Gbeatohkx. Wo scarcely take such matters as part of 

 our regular subjects. For general chemistry provision already 

 made. Other questions answered. — K. N., Lepns, J. Minor, C. A. E., 

 Eipple, Alphard, Knowledge, G. P. Benstead, Garryl, S. S. S. S., 

 Myrven, P. M., Amateur Reader, T. Boyer, D. A. N., Lomax, Boy, 

 P. P. J., Scientia cam Legibus, Novice. Questions either too vagne, 

 or trivial, or unsuitable, or already discussed, or for other reason 

 inadmissible. — Anti-Taranaki. Thanks. — W. S. Yes to both 

 questions. — Theo.-James. Already answered. — G. H. Mortimer 

 wants G. E. V. to toll him how to slip tho bobbin of wire over 

 magnet, and what size wire is. — C. C. C. Newton's theory of 

 comets' tails would only account for a certain definite rate of 

 emission, just as known density of our air and kno\vn force 

 of gravity gives a certain calculable rate for rising of a 

 balloon in still air. Comets' tails aro formed at a much 

 greater rate. — C. Harbap. Questions have been referred to bota- 

 nist. Cannot find space for replies so lengthy. — W. H. Harlaxd. 

 Thanks, but toads in holes now disposed of, and space crowded. 

 — J. C. L., T. .1. WoiniKow, and others. Y'our stories are inte- 

 resting, but, unfortunately, many subscribers consider enough said 

 for present about intelligence in animals. — E. Cox. Observe tho 

 influonco of your protest. — J. C. L. There has been a good deal of 

 it.— MoRK Lic:iiT. Will see about it. — R. HcsipnRF.Y.s. Writer of 

 srticles on lirnin Troubles not acquainted with tho hjnnn tune 



"Midinn;" the nddition to tho echo chords ho devised bimiolf. 

 — Omicuox. What is Rhyolite ? — tt. S. Staxken. Trembling of , 

 fixtMl stars duo to " movements" in our air, not moisture, oi mia- i 

 printed, p. •H2. Planets do not tremble, Ixjcauso they hnvo disc*; | 

 stars are appreciably the merest points. — Uowabk Williams. . 

 U'tter fornanlcd to printers. No, you did not mention our I 

 former nc(|unintance, and I therefore inferred you wore only a i 

 namesake of the 11. W. 1 know at St. John's. — Tiios. Mactaogast. | 

 'Hianks, but no space. — J. Oliisox. C)b, but oxcaso mo; the 

 sijuarcs of + o and — a nre c(|ual. — Cornwall. Thanks ; query i 

 referred to electrician.— U. A. N., J. -M., Ahtiii-k BtcKiiEm, , 

 Brf.ntox, Kit, and others. What is the logarithm of a negative , 

 quantity ? Tho logarithm of a number to a given base is that i 

 power to which the base must bo raised to equal tho number. To 

 what power must any given positive numlwr be raised to make it 

 negative ? It seems scarcely worth while to discuss a paradox 

 thus arising from misuse of a fonction invented for a S|iecial pur- i 

 pose. — C. Harris. Paradoxes well knomi. — J. McGrigob Allak. 

 If you conld only put your objections against vegetarianism into 

 smaller space. — W. H. Wood. Question answered. —Phosphor. Germ 

 theory not inconsistent with evolution. One of your other queries 

 inserted. When one correspondent sends six queries at once we begin 

 to think of closing tho Queries column. — E. M. (Cantab). When 

 tho thcorj' has been established it will bo time to consider how it 

 was originated. — Halivards. Axis of Venus does not point 

 towards sun. No ; I think you saw what yon thought you saw, but 

 that what you saw was not what you- thought it. You are quite 

 mistaken in attributing the origin of tho usage you mention to 

 KxowLKDGE. It has been customary for years, in press, pulpit, and 

 lecture-room, though of course not customarj- with all. It has been 

 adopted in my own case repeatedly. Your i)aper about jelly fish is 

 in type. Will you excuse me if I hint that you have evidently 

 much more leisure than I have. If one correspondent in twenty 

 wrote at such length, or if our circulation increased twenty -fold, 

 as we ho))0 it will, what could a poor editor do ? Replies to 

 such letters as yours would in that case fill all our space. — M. B. 

 Aldeb. Pardon me. I by no means welcome Dr. Siemens' theory. 

 I have given Dr. Cari)enter'8 report of it ; but it seems to me (I 

 venture to say, t( is) utterly untenable. There is no such centri- 

 fugal tendency as he imagines, and sims cannot at same time do 

 the work he describes and shine through interstellar space as they 

 do. — M. Wyatt. Yon don't explain why you take 22 to the power 

 5, and not 21 or 23, or some other number between 20 and 30. — 

 Z.iRES. Y'on have attacked too difficult a subject. — Hebbeet 

 Pickle. Thanks ; but we would rather not encourage such 

 kindness. Your book might not be returned, and we should 

 feel (though you, no doubt, would not hold us) respon- 

 sible.— W." H. PiGRiM. Theory too vague. — W. Smith. It 

 would bo much more convenient if two of the 31-day months 

 gave up one day each to February. But in such matters the human 

 race is ver\- slow to change. — JoBX Carteb. I was thinking rather 

 of cases where the training from the beginning had come into the 

 teacher's hands ; in other words, of cases in which a parent had 

 been the teaelier. I cau well believe there are cases whore bad home 

 training leaves the teacher little choice but to use some form of 

 corpor.ll punishment. — E. V. H. The indications of the spectro- 

 scope are reliable to a certain point ; they do not tell us everything, 

 however. Spectroscopic evidence respeclJvng larger comet presently. 

 — Cabixet Makes. Cannot give addresses of correspondents. — 

 Samuel Stuettard. There was a transit of Jlercury in Nov. 11, 

 IStJl, and one in Nov. 5, 1868; none eighteen years ago. Yon 

 could not have seen au intra-Mercurial planet in transit, if there 

 were one. Most probably, what you saw was a spot, and though 

 "apparently the size of a five-shilling piece" (how far off ?) was, 

 probably, considerably larger. — H. H. Harris. There are many 

 cases in which the old poets made their words resemble in sound 

 what they were describing. I know of none much more striking 

 than tliis, in a description of frj-ing : — 



Qnis non — norit 

 Stridentesqne focis opsonia plebis alausas. 



— N. The illusion is practically the same wliich Mr. Foster has 

 described and illustrated in No. 1. However, it shall appear. — 

 Henry Cabb. It is science which is exactly worded and plainly 

 described, not the magazine. The point you notice was carefully 

 considered in full conclave. — JoHX Hamer. Thanks for kindly 

 letter. As for your explanation, we wait. 



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 Pond's Extract is a certain cure for Hicmorrhoids. 

 Pond's Kxtract is a certain euro for >'euralpc pains. 

 Pond's Extract will heal Burns and Wounds. 

 Pond's Extract will cure Sprains and Bniisce. 



Sold by all Chemists. Get the f^enaine. 



