Jax. 20, 1882.] 



• KNOWLEDGE 



257 



different parts of the eartli's interior, the pressure at any point 

 within the earth is proportional to the total quantity of matter 

 aboTe that point, just as in the sea, where, though gravity is 

 appreciably constant, pressui'e is proportional to the ileptli. If yiiu 

 ask where the force of gravity is at a maximnm, I cannot answer, 

 becsuse I do not know according to what law density increases 

 towards the centre. As to the other point, our circulation 

 increased so that it became iiuite inipos.sible to continue cutting 

 tho edges without unduly delaying publication, lint we more 

 than make up for that in other ways. In binding there 

 would in any case have had to bo another cutting, and 

 most of our readers, we believe, intend to bind each volume 

 as it is completed. — H. Fear cannot find space for jiaper on 

 colours. Headers complain unless a certain proportion of space 

 is given to original matter, and we cannot increase the total space 

 beyond a certain range. Correspondents must not suppose we do 

 not value letters whicli we are obliged to omit.— J. E. Shepiiard. 

 The writer of the article in que.'stion was not likely to consider the 

 use of aconitine in homoeopathic practice. It is seldom used by 

 allopathic physicians, except as an external application. — A 

 Greenock Stuoext. Clouds ai-e formed by the condensation of 

 aqueous vapour into small water di-ops, which, however, do not 

 faJI rapidly like rain drops. It can be shown that the smaller a 

 water drop, the slower its descent through still air. However, a 

 cloud is also constantly changing, as you suggest. Tlie light, feathery 

 clouds consist of particles of ice or fine snow. Colonel Ross promised 

 other papers on blowpipe analysis, but has apparently not yet been 

 able to find time to write them. The blowpipes made on his plan 

 will be rusting for want of use. — Trebob Rol.it. Short whist, 

 played without counting honours, is, to all intents and purposes, the 

 ordinary game with the element of chance as far as possible 

 eliminated. It is in mj' opinion a mnch better game even 

 than that which Clay thought would be perfect, in which 

 the honours are counted at half tho usual rate, one point 

 for two by honours, two for all four honoui-s. After playing 

 the game for any length of time without counting honours, a 

 real lover of wliist feds something like shame in counting honours, 

 or even half honours. At present we fear the star chart cannot 

 be issued with the last week of each month, as we want one chart 

 to appear each month. As soon as we can, the change shall be 

 thought of. Have no space, for some time, for article on relation 

 between mind and physical force. — Doro. Brodie. Your 2i stamps 

 received, but no paper on the Tides has yet appeared ; we did not 

 promise it for an early date, and if we had, we could hardly have 

 kept cur promise. — J.imes Deas. Never heard before that the Star 

 in the East was thought by any one to be the variable Mira. That 

 star has been said to be a comet, a conjunction of planets, and a 

 temporary meteor. Astronomy has nothing to say to any of these 

 ideas.- — S. de Meuvigxe. The passages yon quote show that where 

 the conditions remain the same, races change little or not at all. What 

 is there in the theorj- of evolution to suggest that they should change a 

 great deal ? — F. F. Your suggestion about the use of Jacob's ladder at 

 fires seems excellent, but space should be found for it elsewhere. It 

 does not belong so much to our subjects, as to those treated of in 

 weekly newspapers or mechanical papers. — Vig.noles. Many 

 thanks; but your square has already been given. — Robeetu.s. We 

 do not know the name of the secretary of the Society for Pro- 

 moting the Abolition of Capital Punishment. — E. M. Not knowing 

 ilio tables that you refer to, cannot tell precisely how the dis- 

 crepancies arise. The date of your tables is so remote 

 you could scarcely expect calculations made by them to cor- 

 respond with the recent ones of the Nautical Almanack. Wo 

 shall give s\icli a map as j-ou mention, relating to the 

 transit of Venus. You must not expect to find in tho " Nautical 

 Almanack " all that is necessary to calculate phenomena. I hud 

 !o work many hours and many days to get the results on which I 

 i5ed Biy investigations of the transits of 1874 and 1882. — J. X. 

 'Kvi.VE. Of course yon are right. Our mistake was a natural 

 lie; but it was unquestionably a mistake. We have altered it, 

 noting the error. — Member or the Archeological Society. 

 Thanks ; but it would be an obligation if you could briefly sketch 

 for readers of Knowledge the essential ideas of Narille's book. 

 The subject is a curious one, a little out of my own personal lino of 

 studies, but full of interest, and I am sure readers would be in- 

 terested. 



Mr. W. H. H. Hupson, late Fellow and Lecturer of St. John's 

 College, Cambridge (Third Wrangler in 18iU), succeeds Mr. Drew as 

 Professor of Mathematics at King's College', London. 



Poxb's Exteact is a certain cure for Ehenmatism and Gout. 

 Pond's Extract is a certain cure for Hamcrrhoids. 

 Pond's Extract is a certain cure for Neuralgic pains. 



Pond's Extract will heal 1 



Pond's Extract will cure Sprains and Bruises. 



Sold by all Chemists. Get the genuine. 



fAOTT. 



fiottd on 9it anil ^nrnrr. 



Fer.mexhtion in Beer. — " In Re " is evidently unaware of the 

 lengthy explanation which his (luestiou involves. In tho first place, 

 different brewers have different ways of starting fermentations. 

 The Germans, and a few English, mix their yeast with a little of 

 the •' wort " first, and then add the rest. The Japanese use rice 

 must for starting. Then the " pitching " variations during process 

 of specific gravities and temperatm-e must be considered, also germs 

 generated in fermenting — healthy and unhealthy— the ijreparation 

 of t!ie wort and yeast ; in fact, I should adWse " In Re " to get a 

 book on brewing and read it through, for it will all be interesting, 

 and w-ill lead hirn up to his .nibject. If Dr. Graham, Professor at 

 University College, London, has published his lectures delivered on 

 the subject, I can only say that " In He" will have a book written 

 by one who has mastered thoroughly the whole subject of brewing. 

 Mr. T. A. Tooley, B.Sc, F.C.S., editor Brewers' Guardian, has his 

 articles on Brewing and Distilling, written for the " British Manu- 

 facturing Industries," published. His name needs no comment. — 

 F.C.S. 



The Expansion of Watee by Heat. — Herr P. Volkmann has in 

 the AnnaUn fiir I'lnjfik vnd Chemie compiled the results of Hagen, 

 Matthiessen, Pierre, Kopp, and Jolly, on the expansion of water, 

 and has obtained the following mean results for the volume and 

 density of water at various temperatures : — 



Temp. Volume. 



ISdegr. C 1000847 



1-001731 



1-002868 



1-001250 



1-007700 



1-O11070 



1-010940 



l-022t;iO 



1028910 



1-035740 



1-043230 



■ — Scientific American. 



Sunday Lecture Society. — In the course of his lecture on " The 

 Heart and its Work," on a recent Sunday, at St. George's Hall, 

 Langham-place, Dr. Andrew- Wilson gave some interesting details 

 regarding the action of the central engine of the circulation. The 

 heart, he showed, was merely "a hollow muscle," and the force 

 which drives blood through our bodies is therefore similar to that 

 wherewith we move our fingers in writing, or our legs in walking. 

 Dr. Wilson showed also that the work of a man's heart in 24 hours 

 amounted to 124 ft. tons ; i.e., if the heart's force for 24 hours were 

 gathered into one stroke or lift, it would suffice to lift 124 tons 1 ft. 

 high. The heart is ruled by at least three sets of nerves. In its 

 own substance, there are masses of nei-ve-matter, or jangtia, which 

 carry on the normal work of the organ. Then, secondly, there 

 exists an important vagus nerve, -n-liieh checks or slows the heart's 

 action, as under the influence of fear or other mental emotion; and 

 there is, thirdly, a mjmpathetic nerve, which causes the heart's 

 action to increase in rapidity. The varying emotions of the mind 

 thus influence the heart for good or for evil by disturbing its normal 

 action. 



No Organic Ma-tter in Meteors. — A Louisville (Ky.) paper 

 rejiorts an interview with Prof. J. Laivrenco Smith, of that city, in 

 the course of which Mr. Smith gave reasons for discrediting tho 

 discovery of organic substances in meteors, as claimed by Prof. 

 Hahn, of Berlin. Mr. Smith said :—" Although I have probably 

 examined more microscopic plates of fragments of meteorites than 

 any other person, still I have never discovered anything like organic 

 remains in any of them. Besides, the well-known chemical com- 

 position of these bodies is averse to the existence of any such 

 remains as spoken of by Prof. Halm. Were these remains present, 

 we should discei-n carbonate of lime in their interior. The two or 

 three that have any carbonate of lime were discovered and analysed 

 by myself, and in these cases the carbonate of lime was an accidental 

 constituent of inci-ustation deposited on the surface after their fall. 

 In the microscopic examination of these polished plates of meteorites, 

 tho two predominating minerals, enstatito and bronzite, will, by 

 their fissures and forms, sometimes remind one of vegetable 

 and other organic forms, but the merest tyro of an observer 

 will trace here nothing but a rare resemblance. And further- 

 more, the nature of these minerals precludes the ])Ossibility of 

 organic remains even in terrestrial minerals of similar kind. Not 

 knowing of any eminent German geologist named Prof. Hahn, I 

 thought it but reasonable and logical that I should inquire some- 

 thing about him from mv friend Prof. Hawes, now in the employ of 



