14 



♦ KNOWLEDGE ♦ 



[Jan. 5, 1883. 



rospiration, I snpposo lie nionna that only about ono-tliird of the 

 contontH of tho lungs are rhangid for fresh air in each ordinary 

 act of respiration. True, but it docs not follow from that that tho 

 lungs ara doing nothing with tho two-thirds balance. On the con- 

 tniry, nil that balance of air is obeying meanwhile the law of 

 diffusion oj gases (in this case: tho interchange of oxygen and car- 

 bonic acid, &c.), and the larger the amount of air, and tho greater 

 tho space in the lungs, the more rapidly and perfectly is that all- 

 important interchange effected; so that largo lungs are a desirable 

 possession. E. D. Girdlestoxe. 



A CURIOUS CHRISTMAS. 



[(582J--A rare phenomenon was observabh? ('''-•, outside wiudow 

 condensation) on Christmas day. The outer air was so warm com- 

 pared with that of tho interior of our houses that in all rooms where 

 there was no fire burning the window panes were cold enough to 

 condense the aqueous vapour of the saturated outside air, and were 

 theroforo densely bedewed outsside. 



This only happens with a sudden rise of temperature such as 

 rarely occurs on Christmas day. W. Mattieo Williams. 



anEfluns to Corifsponticnts* 



A Country Clekgyman. It is very diiEcuIt to advise. A telescopist 

 gets an instrument that suits him, and sticks to that ; so that he 

 can say little about other instruments. It is well, however, 

 to be on tho look-oat for advertisements of second-hand tele- 

 scopes by known makers. — II. Bevfus. Think there must be 

 some mistake; will ask Mephisto. — W. Lance. Spectroscopic 

 analysis shows coma to possess inherent light, and that even 

 parts of tail do also.— C. J. T. (1) Do not think Raskin's 

 description agrees with the observed phenomenon. (2) Taking 

 what is said on p. 107, table on p. 106 agrees with Young's. It 

 gives the ecJiptical diameter, not the equatorial. For screen-work 

 only true at solar noon, unless screen carried by telescope driven 

 equatorially. — W. G. By observation of Mars — not a new method 

 — described in my little book on Sun, and in many other places. — 

 XXX. Velocity less at return ; would be the same if there were 

 no air, but effects of atmospheric resistance throughout flight all 

 tend to diminish velocity. — A Builiiek's Sox. Putting the boards 

 apart will make very little difference. It is found, for instance, 

 that the driving force of the wind on the present divided topsail, 

 though rather less tlian on a single topsail of the same area, is not 

 so much less as to indicate greater loss than corresponds to tho 

 diminished area presented when the two sails belly. A parachute, 

 again, has greater sustaining power when a hole is pierced in the 

 centre, though that is due to steadied descent and diminished 

 jerking. — George Clements. Remember how those triple kites used 

 to pull. — PsvcHOMANTis. Thanks ; we quote the passage in Gossip. 

 As to Comet, it was very bright in Australia then ; but its course 

 indicates anything but constant proximity to the sun. — H. Peacock. 

 Ajax not so generally known. Diffractive effects curious. — 

 Cosmas. Thanks : would insert, but matter to same effect already 

 in type. You seem to overlook the real analogy between the strength 

 of wrist or knee muscles, and the strength of waist muscles, which 

 was all we suggested. The question of the interior organs is, of 

 course, much more important. ^Ye cannot understand your doubt- 

 ing whether the subject should find place in a scientific journal. Is 

 a knowledge of our own bodies, and what is good for them, not 

 science ? — H. W. B. B., A Chcrchman. It depends much on indi- 

 vidual tastes; but certain customs — the use of ancient verbiage, 

 tho wearing by clergymen of out-of-date costumes, and so forth — 

 seem to imply that religious teaching, to have influence on the 

 many, must always be more or less behind the age — more in some 

 churches, which actually use a dead language, less in others, which 

 only use old-fashioned speech. I personally have this peculiarity 

 (I suppose it is) of mind, that I muat see such things as they are, 

 free from associations with antiquity, or with recollections of my 

 own past (especially my own childhood), free, in fine, from all false 

 light.'!, before I can satisfy myself as to their value. The very points 

 on which Cardinal Newman dwells are among my strongest reasons 

 for objecting. Not one in a hundred is at the pains to ask 

 how much tho effect of certain words is due to their intrinsic 

 value, how much to the influence of association. Surely feel- 

 ings so excited have no more specially religious significance than 

 those which move the mind when the music of old home days is 

 heard again, <jr when the quiet loveliness of a spring morning or an 

 autumn evening stirs the heart with thoughts of days that arc past. 

 I do not say that we should analyse such feelings and emotions ; I 

 prefer, for my own part, to yiehl to their influence. But it does 

 seem to mo essentia! that we should not mistake these in reality son- 



BuouR effects for religious feirour. The soothing influence of the word 

 Mesopotamia on tho old woman of a familiar story was, we know, 

 akin in her mind to a devotional feeling. No one would wish to 

 dejjrivc her of the soothing effect ; but she might as well know how 

 little of religion there is in it. — C. Caels-Wimon, Wm. Simmo.v.-*, 

 E. C. Thanks; but no space. — Ed. Robinson. It is so far true that 

 no conceivable advance of science could take us back to tho actual 

 beginning of existent things.— Blacki'riah.s. Rest you merry, sir; 

 and, Rest you, merry sir : your effort to be merry deserves it. The 

 passage runs, " Where got'st thou that goose look ? " Perhaps you 

 can say.— W. R. Evs, notes that tlie publisher.^ of I'Abbc lloigno's 

 works are Ganthier-Villars, 55, Quai des .\ugustins, Paris. — C. R. 

 Haines. (1) In a scientific sense, Edgar Poe's " Eureka " is almost 

 without value. (2) The earth's nrbil has not shifted owing to pre- 

 cession ; the position of her etpiator has; but the dates in question 

 would not have been sufficiently altered since the cold spells were 

 noted, to modify a relation which is, any w.av, rather rough. — 

 E. Gvkvey. Have asked for address.— J. H. Green. Every tail 

 would be straight if that theory were true ; but straight tails are the 

 exception. — G. HABKi.'iON. Experiments by Pasteur on Hydrophobia 

 will shortly be quoted. — A. A. Hartley. How does a cinder reflect 

 light ? Why should not the moon ? — H. J. W. Thanks. Do not know 

 where Griffin's excellent treatise on Rigid Dynamics obtainable. — 

 X. Y. Z. You are right ; that old mistake should have been cor- 

 rected. — W. P. Nevixs. Thanks.^ — A. S. Woonw.^Ro. Fear could 

 not find space at present. — M. J. Harding. Have heard nothing 

 about " Half-Hours with Telescope," since it was published in '08. 

 — C. R. Passage would doubtless interest many. — H. J. Mliruead. 

 Subject dealt with in article in Co-nihill recently. — W. E. Collarii. 

 Subjects too wide for brief answers here. — Samson. Can hear of no 

 wooden dumb-bells. A tui-ner would make thera. — W. Morgan. 

 Thanks ; most conclusive. — D. C. Snape. Thanks ; forwarded to 

 electrician. — A Yoitng Man. Thanks. — V. E. A. The series 

 cannot be summed either to n terais or to infinity. — R. Jkkmax. 

 Thanks; but British Israelism is not an inviting subject. — E. S. B. 

 Is not the 10th nearer the middle than the beginning ? I should 

 understand by " early in May," a time within the first week. Thanks, 

 however, for your note. Perhaps I wanted an excuse for saying 

 how much 1 enjoyed the " Golden Butterfly." — W. G. Dr„U"ER. 

 Thanks. The case is curious ; but explicable as a coincidence. 

 There are so many dreams, and so many deaths, that sometimes 

 the right death must be dreamed about. — " Tikhoot." The tele- 

 scope will bear a power of 3,000. In point of size the moon can be 

 seen as if nearer than Mount Everest from yom- observatory. But 

 all atmospheric effects being magnified in like degree, there is 

 nothing like the same distinctness. — L. W. HuTCHiNGs. Many 

 thanks; but several object to much space being given to 

 such narratives. — J. O. Lindsay. JIany thanks. — Pleiades. 

 Astronomy would be rather too severe for mental exercise. Easy 

 geometrical problems would, I think, be useful, especially for 

 out-door thinking.- — D. DoDD. Hopelessly untenable. — E. R. C. 

 No reason whatever for associating the comet of 1883 with 

 Abraham's comet. By the way, which u-a.9 Abraham's comet ? — 

 PnvsiciAX. Short articles of that kind would probably be very 

 acceptable. — J. G. Ashworth. Thanks. Evidence of the kind 

 already in type. "An Observer" is 7wt interested in the sale of 

 corsets. I am only free to say that he is one whose opinion on any 

 subject whatever must be well weighed and well worth weighing, 

 albeit I think he is mistaken in this matter. — A Student. As to 

 Star in the East, see No. 61 ; as to perihelion theory of world's end, 

 it is all rubbish — 



"One half of it ignorance, t'other half rum." 

 — F. W. Reynolds. Photographic perspective often monstrously 

 wrong. I have seen photograph of interior of a Pullman car look- 

 ing at least 300 feet long — the result of relative increase of pai'ts 

 remote from centre. — Wm. Nullar. Without wishing to be dog- 

 matic, or even positive, I think I may confidently say that tho spot 

 you saw on the sun was a sun-spot, not a jjlanet in transit. 



ELECTRICAL. 



Semper Eadem. Bunsen or Grove. — Ignorance. 1. It depends 

 upon the resistance of the battery, and the work to be performed. 



2. Presuming that the circuit will not be a long one. No. 20 copper. 



3. No. 11 or 10. 4. It is immaterial for electrical purposes whether 

 tho conductor be in the ribbon or wire form, providing equal 

 lengths contain equal weights of similar metal. 5. You get no 

 shock, because the resistance of the body is very considerably higher 

 than the electro-motive force of the battery. G. Only by measure- 

 ment, but approximate values may be found with good galvano- 

 meters, wound with coils of thick and thin wire. 7. " When you 

 pass a spark through vacuum there is combustion. What is burnt 

 or consumed ? " You cannot pass a spark through a vacuum, and 

 where there* is no matter there can obviouslv bo no combustion. 



