254 



KNOWLEDGE 



[No\-EMBEB 1, 1894, 



The Physical Society is about to follow the example of 

 the Chemical Society, and in January next will commence 

 to publish a monthly pamphlet of abstracts of papers 

 appearing in the principal foreign journals devoted to 

 physics. There is an urgent need for a publication of 

 this kind in each department of experimental science. 



Prof. Bumham writes: — "A few weeks ago Messrs. 

 Clark tried the new Yerkes 40-inch objective on stars for 

 the tirst time. The result was very satisfactory. Alvan 

 Clark thinks that this will be, when finished, the best large 

 objective ever made. 1 hope to get off to New England 

 in a week or two, and if the weather is good I shall have 

 a chance to look through it." 



Kottccs of Boofts. 



Tlie Rise mill Ih'relopment of I hyanic Chciiiistri/. By Carl 

 Schorlemmer, LL.D., F.E.S. Eevised edition by Arthur 

 ^Smithells, B.Sc. (Maomillan and Co., 1894.) This 

 valuable book has long been out of print, though French 

 and German translations of it have appeared in 1885 and 

 1889. Shortly before Prof. Schorlemmer's death he com- 

 menced to make corrections and additions for a new 

 English edition, sending the manuscript to his old fi'iend 

 and pupil. Prof. Smithells, for correction in English. The 

 book was not proceeded with very far when Prof. Schorlemmer 

 died, and Prof. Smithells has since, at the request of 

 the executors, completed it, and has added a most appre- 

 ciative biographical notice of his friend. Carl Schorlemmer 

 was born at Darmstadt in 1834. He commenced his working 

 life in an apothecary's shop ; his schoolfellow, Dittmar, 

 had become assistant to Bunsen at Heidelberg, and, 

 inspired by contact with Bunsen, Schorlemmer soon decided 

 to give up pharmacy and devote his life to scientific 

 chemistry. In 1859 he became assistant to Prof. Roscoe 

 at Owens College, j\Ianchester, and was soon, at Prof. 

 Roscoe's request, appointed to a separate chair of Organic 

 Chemistry. 



We have received the following books, &c., for notice : — 



Piinds and Bock Pools: tcith Hints on Collecting for and the 



Management of the Micro-Aquarium. By Henry Scherren. 



(Eeligious Tract Society.) 



~ ' ' Works of Constance Xaelen. 



Poetical 



Camille Flammarion, trans- 

 J. Ellard Gore, F.R.A.S., &c. 



llie Complete 

 (Bickers & Son.) 



Popular Astronomy. By 

 lated from the French by 

 (Chatto & Windus. ) 



A Laboratory Manual of Physics and Applied FAectricity. 

 By Ed. L. Nichols. Vol. H., Senior Course. (Mac- 

 millan & Co.) 



Edible and Poisonous Mushrooms. By M. C. Cooke, 

 M.A., LL.D. (S. P. C. K.) 



Our Secret Friends and Foes (Micro-Organisms). By 

 P. F. Frankland, Ph.D., B.Sc, F.R.S. (S. P. C. K.) 



Fruit Culture for Profit. By C. B. Whitehead, B.A. 

 (S. P. C. E.) 



Text Book of the Diseases of Trees. By Prof. R. Hartig. 

 English translation. (Macmillan & Co.) 



Manual of Physico-Chemical Measurements. By W. 

 Ostwald. English translation. (Macmillan & Co.) 



From the Oreelis to Darwin : an Outline on the Derclop- 

 ment of the Evolution Idea. By Henry F. Osborn, D.Sc. 

 (Macmillan & Co.) 



The Slide Rule: a Practical Manual. By Chas. N. 

 Pickworth. (Emmott & Co., Limited.) 



Photo-Mirroiiraphi/. By Dr. Henri Van Heurck, trans- 

 lated by W.' E. 'Baxter, F.R.M.S., F.G.S. (Crosby 

 Lockwood & Son.) 



Falk'n Anyels : a Disquisition upon Human E.vistence. 



By One of them. (Gay & Bird.) 



Froyn Spriny to Fall : or when Life Stirs. By a Son of 



the Marshes. (Blackwood.) 



Amjihio.nis and the Ancestry of the Vertebrate. By 



Arthur Willey, B.Sc. (Macmillan & Co.) 



Report on Met^orohyical (Jbserrations in Hritisli East 



Africa, for 1893. By E. G. Ravenstein, F.R.Met.Soc. 



(Geo. Philip i^- Son.) 



Practical Physioloyy of Plants. By Francis Darwiu, 



M.A., F.R.S., and E. Hamilton Acton, M.A. (Cambridge 



University Press, 1894.) 



The Royal Natural History. Part 1:2. (F. Warne & Co.) 



Science for All. Part 67. (Cassell .t Co.) 



The Universal Atlas. Part 1. (CasseU & Co.) 



Inde.v to World's Technical and Scicntijic Literature. 



Sections I., II., and III. (Romeike & Curtice.) 



31 c 1 1 c V s . 



[The Editor does not hold himself responsible for the opinions or 

 statements of correspondents.^ 



To the Editor of Knowledge. 



De.ir Sir, — The article by Mr. Evershed in your October 

 number recalls some questions that I tried to answer, and 

 some experiments made by me some twenty years ago, 

 and which, I think, tend to confirm his conclusions. 



It seemed to me that in the production of light for 

 illuminating purposes, we were, as a Chinaman would say, 

 "burning our house down to roast the pig." In fact, we 

 were using a large quantity of energy in heating up bodies 

 so as to become luminous, and getting a very small amount 

 of that energy utilized in the production of light. It 

 occurred to me that if it were possible to set up in the 

 molecules of the body used vibrations of a high light-giving 

 order only, none or only a small portion of the energy 

 would be wasted in heat radiation. 



The method of electrical excitation in tolerably high 

 vacua seemed the most promising one to follow, and I 

 estimated the quantity of heat produced in gases in various 

 tubes under various conditions of vacuum and current. 



For my present purpose I need only say that the heat 

 simultaneously given off was large, and I had not produced 

 light vibration alone by any means. 



On consideration of the experiments, I could see no 

 difference in the light and heat-giving effects batween the 

 gas electrically luminous, and what one would expect to 

 find if the same were rendered luminous by heating in the 

 ordinary way. I concluded that whether a gas be excited 

 electrically, or chemically, or by ordinary heating, its 

 vibration is of the same kind, or at least there is nothing 

 pointing to the contrary, and my expectations had been 

 misled by the fact that gases under electrical excitation are 

 usually very rare, whereas when ordinarily heated they 

 are at atmosphei-ic pressure, or thereabouts. 



The exact manner in which heat, chemical, and electric 

 excitations act on the molecules of a gas is unknown ; but 

 is there anything to show that the result of the action of 

 one on a gas is different in kind to that of another :* 1 

 expect not. I picture to myself the molecule of a gas, at 

 ordinary temperatures, rapidly changing its shape to a 

 small extent, in the manner of a soap-bubble just released 

 from a pipe ; under greater excitation, at higher tempera- 

 tures, I imagine waves running over its surface, and 

 under still greater excitation, ripples on these waves. It 

 is these waves and ripples that produce heat and light 

 through the medium of the ether — certain waves and 

 ripples, fitting the size and elasticity of the molecule, being 



