116 



♦ KNOWLEDGE 



[Dec 9, 1881. 



tliiiiR. tlicy will floiirish ; if tliov iiro worllilpHS, tlipv will die. I 

 dliimlil conaidiT tlicm of not iiiucli vjiluo if I tlioiight they would 

 Roiu'rally bo ncrpptcd witliimt n linrd Imltlr. 



It may perlinps bp ns well to iiifomi tlie general render tlint my 

 views do not in any way affect I lie working of tlioge mathematical 

 problems which are based upon the facts and phenomena of Nature. 



Newton Ckoslanh. 



THE FAURE ACCUMULATOR. 



[01] — As one who has read and recommended several friends to 

 (fct KsowLKnoR, might 1 nsk a favour? 



Much mention has lately been made of the " Faure Accumnln- 

 tor," and the benefits likely to accrue by this addition to electrical 

 appliances, but I, like a good many more, have no very clear or 

 precise idea as to what this invention is. 



Would you therefore give in a future (and let mo lioi>e near) 

 number of Knowlekge, an account and description of it ? 



A SCIKNTIFIC- SmATTERER. 



FAURE ACCUMULATOR.— GRAVITY. 

 [95] — Would you kindly furnish me with a short account of the 

 ■construction and mode of action of the Faure Accumulator ? also, 

 if not asking too much, the proof, or where it is to be found, of your 

 statement concerning gravitv, on page 59, No. 3, of Knowledge ? 



G. T. 



PRACTICAL WORK WITH THE TELESCOPE. 



[96] — In reply to your correspondent " G. M.," letter 39, I would 

 suggest for his use the Rev. T. W. Webb's " Celestial Objects for 

 Common Telescopes," new edition, and R. A. Proctor's " Larger 

 Star Atlas," 4th edition ; and that he might do very u.seful work in 

 carefully observing and recording the colours of stars, and the 

 changes of brightness of some of the variables. 



With best wishes for the success of Knowledge, I am, dear Sir, 

 yours faithfully, 



JosErn Baxexdell. 



THREE-SQUARE PUZZLE. 

 [97] — The enclosed has never been published in any book or 

 periodical, but you are welcome to insert it in yoiir paper, Know- 

 ledge, if you think well to do so. If a piece of cardboard is 

 cut into the five pieces, A B C D and E, it is not easy to form 

 the third large square with them. This makes a good puzzle for 

 Christmas. 



Arrange the five pieces A B C D E, which compose the two small 

 squares Nos. 1 and 2 into a single square. No. 3. This, when done, 

 is a mechanical proof of the above proposition. — Yours &c., 

 Alf. a. Lanoley, 

 Engineer-in-Chief, Groat Eastern Railway Co. 



REPORTS OF SOCIETIES. 



[98] — Truly, as the " announcement " of Knowledge was 

 originally gratifying to those who seek it, and equally as truly as the 

 publication itself proves so, still, you will not wish the compliment 

 of having got " one subscriber " to be often rci>eatcd to you. In 

 my humble case I ordered three on " spec " of No. 1 before publi- 

 cation, and at once posted one off to the Australian up-countrj- — 

 the latitude somewhere where you did sec what " Parallax " says 

 lot. 



And after saying this, may I find a little fault ? I mil venture. 



It is in the omission of any chronicle of tho proceedings of the 



learned socicticB, both home and foreign. For instance, the 

 Meteorological met on tho ICth, and discoursed on the big storm of 

 Oct. 11. Now, sir, this feature is a great desideratum, and, there- 

 fore, let me urge it strongly ; and also that the reports, however 

 brief, be systematic and real. There surely would have been 

 something most interesting to report concerning Professor Tliompson 

 on the " Storage of Electricity." And even the mental science 

 societies should not be left out in the cold. The " Aristotelian," for 

 instance, could tell the world briefly of its goings on in the " know- 

 ledge " of its mind-work. — Yours, &c , J. F. S. 



AQUEOUS VAPOUR. 



[99] — In letter 20, on page 50 o{ your welcome paper, G. F. P. 

 Dyer makes a statement about aqueous vapour, of which I venture 

 to question the accuracy. He sjiys " that aqueous vapour has the 

 jjower to ab.sorb rays of hent coming from the earth, but is incom- 

 ]>etent to absorb rays from the gun.'* Now, in " Heat as a Mode of 

 Motion," Professor Tyndall stales (paragraph CRl) that experiment 

 proves that the aqueous vapour of the atmosphere absorbs about 

 four-tenths of the heat radiated from the sun towards the earth. 

 Has subsequent experiment disproved the Professor's conclusion, or 

 has Mr. Dyer made a mistake ? I think in this case Dr. Tyndall 

 must be right. H. P. 



[H. P. will find, on more careful reading of paragraph 68^1, that 

 Dr. Tyndall docs not say exactly what U. P. has stated above. It 

 is, however, true that aqueous vapour absorbs a portion of the sun's 

 heat-rays, but in much smaller jiroportion than it absorbs the obscure 

 heat-rays from the earth. — Ed.] 



FLOWERS OF THE SKY. 



[100] — May I take the liberty of calling your attention to certain 

 passages in your work, " Flowers of the Sky ?" 



In page 2, the velocity of light, "at a rate exceeding more than 

 ten million times the velocity of the swiftest express train." 



In page 15, " that light carrj'ing its message at a rate exceeding 

 sis thousand times the velocity of the swiftest express train, would 

 be utterly unable to give a tnie account of the position and move- 

 ments of the celestial bodies." 



Again, in Figs. 17 and 18, the remarks that apply to 17 belong to 

 18, and vice-versa. — Yours, &c., Wilhelmina K. 



[I have not the book by me, but, unless I mistake the passage at 

 (jage 15, it does not indicate what the velocity of light is, but a 

 velocity which, though enormous, would utterly fail to do what 

 light does. Figs. 17 and 18 got interchanged somehow after the 

 book had been passed for press. — Ed.] 



INTONATION IN SYNAGOGUES. 

 [101] — In an.swer to your coiTespondent ".G. P." The accents in 

 the Hebrew Bible supply the place of musical signs. Warschawski. 

 in his "Progressive Hebrew Course and Music of the Bible," 

 (London: Longmans, 1870), gives a series of equivalents for each 

 of these accents in modern musical notation. For the accents 

 themselves, see any large Hebrew Grammar. With regard to what 

 may be called a cognate matter, the chanting of the Koran, Lane, 

 in his " Modem Egyptians," gives the musical notes which would 

 express the mode in which the first chapter is chanted. There are. 

 of course, full treatises in Hebrew and Arabic on these subject .■', 

 from which deductions could be drawn : this, however, would 

 require much patient research. W. A. S. 



A NEW COMPARISON OF POISONS. 



[102]— In your last number (No. 4) you give an abstract from the 

 Times, quoting the result of a number of experiments of the action 

 of poisons in solution upon fish. Is there not some mistake in 

 relation to the poisonous properties of lithium and barium. The 

 paragrajih runs thus :— Lithium (atomic weight 7, not 17), with 

 an atomic weight only the twentieth of that of barium, is three 

 times as poisonous. Now, it is generally kno>>Ti among chemists 

 that barium (especially the chloride) is an exceedingly poisonous 

 metal (er salt), whereas lithium, even in comparatively large quanti- 

 ties, is not poisonous, the citrate, for instance, being often pre- 

 scribed for gout. 



I think some mistake must have l>een made in copying the 

 original, which, of coarse, is no omission on your part, it being 

 merely an abstract. Wishing your valuable journal all success. — 

 Yours, A-c, Technical Chemist. 



[The " copy " was the paragraph itself . Thanks for pointing out 

 the inaccuracy. Newspaper science needs such correction, as we 

 know from articles and jjaragraphs on subjects more especially our 

 own than technical chemistry. — Ed.] 



I 



