i68 



NATURE 



\ytine 24, I < 



no longer accept any statement, no longer receive any 

 reading, however strongly supported by authority or 

 backed by ancient tradition, unless it be corroborated by 

 the potent instrument of comparison. The modern scien- 

 tific method is the bar before which our classical studies 

 must all be brought. 



The truth of this may be seen at once by comparing 

 the contents of our modern philological periodicals with 

 those that were published at the beginning of the present 

 century. The material still remains the same, but the 

 spirit, the method, and the aims have all been changed. 

 In this, as in the science of language itself, Germany has 

 led the way; but the example of Germany has now found 

 able imitators both in this country and in America. The 

 English Joitnial of Philology has been too long in exist- 

 ence for its merits to need more than a passing recognition, 

 and the American Journal, the first number of which has 

 just appeared under the editorship of Prof. Gildersleeve, 

 promises to be a worthy rival of its Enghsh forerunner. 

 At present, indeed, most of its articles have a touch of 

 "rawness" inseparable from a new venture, but a large 

 part of it is occupied in a most useful way by an analysis 

 of the articles that have been published in kindred foreign 

 serials. This is a feature that might be imitated with 

 advantage by the English Journal. Both publications 

 admit Oriental and general as well as purely classical 

 subjects, and an article in the last number of the English 

 Journal by Prof. Robertson Smith on " Animal Worship 

 and Animal Tribes among the Arabs and in the Old 

 Testament," is marked by his usual learning and acute- 

 ness. He shows in it that Mr. Maclennan's theory of a 

 primitive totemism in connection with polyandry is fully 

 confirmed by the early beliefs and practices of the 

 Semites. A new light is thus cast upon the beginnings 

 of Semitic religion, and obscure allusions in the Old 

 Testament are cleared up. A. H. Savce 



OUR BOOK SHELF 

 Fern Etchings : Illustrating all the Species of Ferns 

 Indigenous to the North-Eastern United States and 

 Canada. Second Edition. By John Williamson. 

 (Louisville, Ky., 1879 ) 

 A H.\NDSOiiE book, consisting of etchings, with accom- 

 panying letter-press descriptions, ot sixty-eight species or 

 varieties of ferns, natives of the northern part of the 

 American comment. The drawings are well executed 

 and characteristic, giving a faithful idea of the general 

 habit of the fern, though without any enlarged details ; 

 and the accuracy of tlie descriptions is insured by borrow- 

 ing them from Gray's " Manual " or Eaton's " Ferns of 

 North America." Of the species depicted, including all 

 that are natives of the Northern United States and 

 Canada, twenty-two, or about one-third, are also natives 

 of the British Isles. The southern limit for the volume 

 appears to be Virginia and Kentucky. The volume is an 

 elegant ornament to the drawing-room table. 



LETTERS TO THE EDITOR 

 [The Editor does not hold himself responsible fir opinions expressed 

 by his corresfotdinls. Neither can he undci'take to return, or 

 to correspond with the writers of, rejected jnanuscripts. No 

 notice is taken of anonymous eo?nnninicalions. 

 [ 77^1; Editnr urgently requests correspondents to keep their letters as 

 short as possible. The pressure on his spare is so great thai it 

 is impf.'^sibU otherwise to ensure the appearance even of coin- 

 viunicatioits containing ijiterestlng and noz'cl facts, 1 

 A Fourth State of Matter 

 Ix the ve'y interestin;j; communication from Mr, Crookes on 

 " A Fourth Stale of Matter," which is contained in N.\.ture, 



vol. xxii. p. 153, there is a paragraph at the end which advances, 

 as it seems to me, some most disputable propositions. 



Like many other questions of modern science, the question he 

 raises is to a very large extent a question of definition. But 

 questions of definition are questions of the very highest impor- 

 tance in philosophy, and they need to be watched accordingly. 



Speculating on tlie ultimate conceptions of Matter which are 

 affected by the discovery of it in "a fourth condition," Mr. 

 Crookes says : ' ' From this point of view, then, Matter is but a 

 'mode of motion.'" 



It has never appeared to me that this well-known phrase is 

 a very happy one, even as applied to Heat. It is possible, of 

 course, to consider Heat from this point of view. But then it 

 is equally possible to consider all oilier phenomena whatever 

 from tlie same point of view. Not only Heat, but Light, Sound, 

 Electricity, Galvanism, and Sensation itself in all its forms, may 

 be regarded as " modes of motion." 



But at least in the application of this phrase to Heat there is an 

 intelligible meaning, and not a mere confusion of thouglit. But as 

 applied to Matter — as a definition of our ultimate conception of 

 Matter — it appears to me to confound distinctions which are 

 ]irtmary and essential. " Motion" is an idea which presupposes 

 Matter and Space. Motion has no meaning whatever except the 

 movement of Matter in Space. To define Matter, tlierefore, as a 

 "mode of motion," is to define it as Matter in a state of motion. 

 But this definition necessarily implies tliat Matter can also be con- 

 ceived as without motion, and accordingly Mr. Crookes is obliged 

 to confess that "at the absolute zero of temperature inter-mole- 

 cular movement would stop," and that after that, Matter would 

 remain with all the "properties of inertia and of weight." 



Again, Mr. Crookes says : " The space covered by the motion 

 of molecules has no] more right to be called Matter than the air 

 traversed by a rifle-bullet can be called lead." No doubt this is 

 true ; but it implies what is not true, that the common idea of 

 Matter ij nothing but "the space covered by the motion of 

 molecules." The popular ideas attached to words of primary 

 significance may not be always adequate or complete. But in 

 my opinion they are generally much more near the truth and 

 more accurately represent the truth, than most of the phrases 

 which scientists are now inventing in the region of transcendental 

 physics. 



These phrases have their value and their interest as represent- 

 ing special and partial aspects of phenomena. But I hold that 

 the unconscious metaphysics of human sjieech are often the 

 deepest and truest interpretations of the ultimate facts of nature. 



June 20 Argyll 



The Fine Wire Telephone 



I HAVE just read in Nature, vol. xxii. p. 13S, an abstract of 

 the Proceedings of the Royal Society of London, giving an 

 account of a new form of telephone receiver devised by Mr. 

 Preece. 



It happens, very curiously, that I was led independently to 

 construct a practically identical instrument, with which I have 

 been experimenting for some time in the laboratory of my 

 colleague, Prof. Tait, and which was exhibited in action at the 

 last _nieeting of the Royal Society of Edinburgh, before I was 

 aware of Mr. Preece's invention. 



The experiments of Mr. Preece and 'myself have been to a 

 considerable extent anticipated by some results given in a paper 

 by Dr. Ferguson (Proc. R. S. E., 1S77-78, pp. 62S et scqq.), of 

 which I was unaware when I made my own experiments. 



It is true that Dr. Ferguson has not applied his apparatus to 

 the transmission of music or of articulate sounds, as has been 

 done by Mr. Preece and myself; but he made the practically 

 very important step of attaching a mechanical telephone to the 

 wire wliich conveys the varying current, and has thus rendered 

 the observation of De la Rive's sounds in iron and other metals 

 both easy and certain. 



In Dr. Ferguson's paper will also be found a most important 

 result, which I have verified since he drew my attention to it, 

 viz., that sounds can be produced in fine wires generally by in- 

 duction currents of vei-y feeble total heating effect. 



As to the theory of the action of this new kind of receiver, I 

 agree witli Mr. Preece that in weakly magnetic metals generally 

 it is due to heating effects. I had been discussing with Mr. 

 Blyth the theory of his receiver (described in Nature, vol. xix 

 p. 72), and it was as an illustration of the explanation of all 

 kinds of microphone receivers, suggested by his beautiful experi- 



