152 



KNOWLEDGE ♦ 



[JOLY 28, 



AX IXSriROMETER. 

 [495—1 »c<> from one of vonr iMijiors on " How to get StroiiR," 

 that queries as to the '• Inspiromotor " have been numerous. 

 Would yoQ eicuse mv mentioning a simple kind of " mspirometer 

 which f made after I had the pleasure of reading the first paper 

 under this title ? The enclosed dramng shows its construction. 



It consists of two tin cylinders, the one — 15 iutlies long— sliding 

 inside the other, which is 10 inches in length. Each of them has a 

 flat end, but the end of the hirgcr cylinder is soldered in about one 

 inch from the eilpe ; 80 that, when i)lacpd " on end " on a table, the 

 depth of each c ylinder from top to bottom inside is the same, viz., 

 15 inches. The object of having the end of the larger cylinder one 

 inch from the e<lge, is to allow space for a J-inch block-tin tube, 

 which passes through the side of the cylinder, alongundcr the bottom, 

 and, going up through the centre of the bottom into the interior, 

 in a etraifht upward direction, terminates about half-an-inch from 

 the top of the cylinder. The cylinder is filled with water up to 

 nearly the top of 'this tube, and the smaller cylinder is then put in, 

 mouth downwards, into the larger one ; it would, of course, sink 

 gradually of its own weight, pressing out the air through the tube; 

 but it is fastened to the end of a cord, wliich, passing over a pulley, 

 luis a weight at the other end which keeps it just balanced. I apply 

 my mouth to the lower end of the tube and draw the air out of this 

 up|>cr cylinder, which descends according to the quantity of air 

 tliat paeses from it into my lungs, and that quantity is shown by 

 figures on the outside of the moving cylinder, forming a register of 

 ii.f-hcB, Ac, as they (the figures) descend. 



Tljis cheap contrivanco sprvcs the purpose as well as any 

 ':< licately-deviscd and finely-elaborated machine. 



I am afraid to trouble you with this communication, but if I am 

 meri'ly obtroding frxjlishly on your attention, pray excuse me, as 

 yon pass this into that receptacle familiar to you, called the "waste 

 lioaket." I at least remain, — Yours very respectfully, 



Ghi^ow, July },\HH>. .\ ill C U S. 



Sn£Au(r£( to Corresfpontientsf* 



for t\t EJilor rrguiriitg tarty itttfntion lioittd r«if* the 

 be Salarday , r,c,d<«g Ikt ciirrtHl iMio of Kkowlidok. Ilie 

 qf ir»i<-» conpelt «• lo go lo prnr earln in tit «•«<•<:. 

 HlKTs'lo ComSBPOliDlilis.— 1. yoqunliom atking /or ninlific t-forwaUoH 

 m t» «».«■«■«/ IkrOHgh Ih, foil. 2 L,ller, •rut lo l\i KMorfor corrnpot,dtnU 

 M.nl hi fbrraidid. nor raa l\t ii<ii»f» or addrrutt of corrttfondeMn te nven in 

 '--If iKauirirt S. Corrfrpondmlt .»o«M Tiilr on o«» fidt otlf tjfat 

 ilrariKQi on a .rti(ir(i(« Irnf. i. Euch lelirr thould havt a till; and 

 l.tirr, r^ertnct ihould be madt to i(. ntiinlcr, Ike page on xkick it 

 title. 



'•»"■»■ I' P' 

 Jiupfr, nnd f 

 IN replying ■ 

 itfpeara, u» 



FAiiEn.\T. Suggestions forwarded to author of those papers. 

 Many thanks. Glad the look of Volume I. idcascs yon.— CupiDis 

 CoGNOscERE. Thanks for extract from recent number of Txt-Btls .- 

 " Prof. Proctor says the sun never lacks a sniiply of fuel, and that 

 it will retain its energy and perpetuate its beneficent work eternally. 

 \\'e brcatlio easier now. An impression has got abroad that the 

 sun would burn out in 17,000,000,000,000 years." This joke 

 jiromises to last about that time. The passage appeared first in 

 an American paper, nearly ten years ago. (2.) You ask, Who is 

 I'rof. Proctor ? In 1873, about Oct. G (having Bailed from Liverpool 

 on Oct. i, and been sick and sorry in the interval) I was first 

 addressed as Professor Proctor by American fellow passengers; 

 and thenceforth, I have been usually so denominated in America an<l 

 by Americans. Thev mean it pleasantly, and I like them too well 

 to object, — though' I have repeatedly explained to them that 

 not only' have I never been a professor, bnt 1 have never 

 iM-en a candidate for any professorship, and have on four 

 distinct occasions declined professorships offered to mo,— three, 

 on very generous terms, in America (I have a presentiment 

 I shall one of those days accept one of these tempting offers), and 

 one in this countrv— the Professorship of Astronomy and Mathe- 

 matics at the Catholic University, Kensington. Thus I am so 

 eniphalically non-professorial that I might almost be called anti- 

 profcssorial. (.3.) You ask. What is the meaning of the statement 

 about the sun ? There you are " too many for nic." I have not 

 the least idea.- Tkia. I refer to periodic changes of the major axis 

 in length, not to variation of the epoch, or to effects of ether.---A. 

 Britl.\nd would like to know the date and place of the death ol 

 Edward Simpson, known as Flint Jack, the ingenious forger ol 

 fossils, flint implements, and Roman anti(iuiiiia. Perhaps some 

 reader can tell him ?— Tabaxaki. Thanks. Coinetion forwarded 

 to writer of those articles.—.!. F. Simpson. The trouble is as to space ; 

 the readings for one place only would be of little use, and not har- 

 monise with the maps. On the other hand, to give two registers 

 dailv, fourteen weeklv for each datum registered, for a score or so ot 

 places, would take much space. Will, however, think of the suggestion. 

 --F C S. The subject of your plan is a littleoutsidoour purpose.- 



(1) You are right 

 difference between the sidereal i 

 earth's revolution is erroneous, 

 wardly motion (along the ecliptii 

 motion of the sun requires indei. 

 other mistake about longer axis of 

 wards has been re])ented so often t 

 not being corrected in the astronomical part 

 mathematical "*- "•-■'" *'■'•"' 



statement that the 

 ill 11- day proves the 

 iiK the sun's west- 

 t due to a real 

 Mion. (2) Tin- 

 ,i.| )»iinting raoon- 

 li;inlly wonder at its 

 of a book by a non- 

 iroof of the 



TOBACCO AXD CONSUMPTION. 



'4SC] — I cannot see that the prevalence of phthisis in men or 



-.-. !^ri,. h is ;.iv .irKuniciit in favour of or against tobacco smoking, 



i own under what circuniHtances they live, and to 



■r.g. Except in the lower elaBBi'«,the life of woman 



•. life of man. Personally, whilst a smoker, I had 



:. my lungs, which I attributed to breathing through 



I rarely smoke now, and always use my nose for 



l,.-.:i'!Mng purposes. 1 have ne%-er bf«n ho free from colds. I will 



not (.'ive my experience of trying to inhale tobacco smoke, as it was 



disaiitrouj. Jobs Alex. Oi.ijkBD, F.R M.S. 



,. ..riter. Airy's geometrical . 

 nature of the tidal motion may hereafter find space here. 

 (3) I do not remember such a passage in Newton s works. 

 I suppose he noticed that as the surface of tho water m 

 a bucket at the polo would be paraboloidal, with a defimtr 

 focus to which light ravs would bo reflected, there would not only 

 (theoretically) be jiroof of tho earth's rotation, but the means of 

 measuring its rate. Tho idea is a pretty one. I would suggest 

 substituting mercury, as water at the pole would probably freeze- 

 so, indeed, would mercury, part of tho time.-TaiA. After getting 

 , =-log (1-t), you proceed "if(=-], «--cOi ought it not to 

 bo -l-x, ■<" Decidedly it ought; and it is. For smce log. (l-<) 

 = -», wo liavo (1-t) ■=c-: whence when (-1, e--0 «c — » . 

 Wherefore /<- cc.- G. G. Bf.azlev. Many tl.nnks ; have forwarded 

 your note to tho publishers. - Sindex. (1) You should havo 

 referred to number, page, and column. 



you that the apparent size of a cloud „ i. » 



(from observer) remains tho same. (I>'«t°''Cefrom earth perhaps.) 

 I do not remember answering aljout any such subject. (2) What M/t 

 vou mean by saying that I "seem to lose no opportunity of exhibit- 

 ing " 4c , ie. ? Where hasany'such feelingbeen shown once even in 

 these pages? If you choose to regard every scientific statement 

 which you cannot reconcile with " <Stc.," as an e.vhibition Of <tc., 

 ic " that is not my fault. But yon should not misreprosent 

 matters. For my own pa.t, I find readers like yourself lose no 

 opportunity of exhibiting ihtir views about ic, ic. (3) fho 

 theory you refer to is jirepostcrons ; it is also an old one, long since 

 disposed of.- G. St. Claib. How can I give any opinion about 



ertainly have not told 

 i-ary while its distanco 



