Aug. 27, 1874J 



NA TURE 



335 



organic compounds, and Dr. Armstrong arranges them 

 all under the following nine heads : — Hydrocarbons, 

 Alcohols, Ethers, Aldehydes, Ketones, Acids, Anhydrides, 

 Amines, and Organio-Metallic Bodies. To each class he 

 devotes a few lines of explanation ; in fact, the whole 

 chapter is a general outline of what is to follow, and is 

 very useful as giving a general and comprehensive view 

 of the whole subject. The kind of action exerted by the 

 most important reagents on organic bodies is next de- 

 scribed, and will be useful to the student who already has 

 some knowledge of the bodies acted on. After thus 

 disposing of these introductory matters, the systematic 

 study of the different classes of bodies above named is 

 commenced and carried through, chapter by chapter, 

 nearly in the above order, the study of Carbon itself 

 forming the starting-point. 



The book will certainly prove of great use in this 

 country and do good service in extending a knowledge 

 of organic chemistry. Students in general will hardly 

 look upon it as an interesting text-book ; long lists of rare 

 substances, whose only real interest at present is in their 

 constitution, cannot be made very attractive. The descrip- 

 tions, however, of important methods of preparation and 

 of purification of different bodies are very well given, and 

 there is a reality and freshness about them which is not 

 generally met with in systematic works on organic 

 chemistry. Dr. Armstrong has evidently not been con- 

 tent to obtain all his information second hand. 



The book will probably become the standard text- 

 book on organic chemistry in this country, and in future 

 editions probably will develop into a larger ^work ; at 

 present even it contains much detail, and is suited rather 

 for the advanced student than for the mere beginner. 



LETTERS TO THE EDITOR 



\The Editor does not hold Jiimself responsible for opinions expressed 

 by his correspondents. No notice is taken of anonymous 

 communications \ 



Mr. Herbert Spencer and Physical Axioms 



In my letter, published in Nature, vol. x. p. 104, I .isked 

 the following question — Does Mr. Spencer regaid the second 

 law of motion as .in " unconsciously-formed preconception," or 

 as a " corollary of a preconception," or as a " conscioiisly-foimed 

 hypothesis " ? 



This led to a correspondence with Mr. Spencer, which he has 

 thought well to publish, with comments, as part of a pamphlet 

 containing appendices to his foimer pamphlet entided "Mr. 

 Herbert Spencer and the Briush Quarterly Reviewer." Conse- 

 quently, I should be glad if you would allow me space for a few 

 final words to state what now appears to be the result of the 

 controversy. 



IJy the fuller explanation widr which Mr. Spencer has 

 favoured me, it has now been made clear that, on his theory 

 of the evolution of physical axioms, the second law of motion is 

 not itself a "preconception," but a "corollary of a preconcep- 

 tion," that is, a truth implied in, but only evolved by conscious 

 mental processes (rom, the preconception ; though he afieiwards 

 somewhat qualifies this statement l)y admitting conscious obser- 

 vation to have its share in the result, when he says, " Obsei-'atio:: 

 aids in disentangling the truth that this re'ation between force 

 and motion is mm e distinct where the actions are simplest— so 

 leading to the intuition that the proportionality is .absolute where 

 the simplicity is absolute." 1 stale this, in fairness to Mr. 

 Spencer, because he lays stress on the distinction, and rightly so 

 from the point of view of psychological theory ; though as re- 

 gards my argument that the second law of motion is not to be 

 regarded as in any sense an <i priori cognition, it is a side issue of 

 no importance. 



But with respect to the maiLi issue, I have at length obtained 

 a definite reply in a pass.age which 1 proceed to quote from Mr. 

 Spencer's comments on my last letter to him. I had said — 

 " Various hypotheses as to the relation between force and change 

 of motion may be made, all consistent with the general precon- 

 ception of the proportionality of cause and effect, and betweeir 

 which the mind alone is unable to decide, until it calls to its aid 

 conscious observ.ation or experiment." To which Mr. .Spencer 

 rejoins — (the italics are mine) — "This is perfectly true. I have 

 said nothing to the contrary. My argument implies nothing to 

 the contrary. I am not concerned with the ijucstiou lioxo impressed 

 force is to be measured, or hcnv alteration of motion is to be measured. 

 The second law of motion is & purely abstract statement, and I 

 hold it to be <l piiori only in its abstract form. It asserts that the 

 alteration of motion (a right mode of measurement being as- 

 sumed) is proportional to the impi-essed force (a right mode of 

 measurement being assumed). I do not affirm that we know, 

 A priori, in what terms of space and time and mass change of 

 motion is to be expressed. The law, as formulated, leaves this 

 unspecified ; and all I hold to be h priori is that which is alone 

 stated in the law." 



To the mathematician and physicist, comment on this is hardly 

 necessary. I was right when I said, in a former note, that there 

 is little left to argue .about. The osteologist ni.ay doubtless for 

 his own purposes speak of the skeleton of a horse as a horse, 

 though the dry bones would be a sorry substitute for the living 

 animal to a man who wanted it to do his work. And so, too, 

 Mr. Spencer, as a psychologist, might (if it did not lead to that 

 disastrous confusion which we have complained that his use or 

 misuse of the terms of physical science does lead to) speak of the 

 second law of motion " in its abstract form " as the second law of 

 motion ; but assuredly Newton, who had carefully defined quan- 

 tity of motion and of motive foi'ce before enunciating his " Axio- 

 mata sive Leges Motiis," did not regard it as a " purely abstract 

 statement ;" and every mathematician and physicist, who has to 

 any extent followed in Newton's steps, knows that all that gives 

 life and force — that is, power to generate new results and to 

 co-ordinate and explain the external phenomena with which 

 physics is concerned — to this or any other physical axiom is nor. 

 its (5 /;wr/ basis or abstract form, but that element in it whii.h 

 has been derived from conscious observation or experiment. 



The upshot of the whole controversy, then, is that lire physical 

 axioms ol Mr. Spencer are not the living truths which form the 

 basis of the physical sciences, but the bare abstract foims in 

 which those truths may conveniently — possibly Mr. Spencer 

 would say must — be expressed. I trust that the value of this 

 result, to the readers of Mr. Spcr.cer's first principles, may be 

 some atonement for the space and time which the contioversy 

 has occupied. RoiiERT B. II.wwaru 



Harrow 



Darwin on " The Origination of Life " 



We are constantly meeting with an objection to Mr. Dai-win's 

 writings, ui-ged alike by friends and foes, on the score of his not 

 having published his views concerning the origin of life. As this 

 objection refers to a matter of literary taste rather than to any- 

 thing of substantial importance, in ordinary cases it is best met 

 by silence; but when a President of the British Association gives 

 it a prominent position in his inaugural address, it is time that a 

 dissentient view should be raised. 



Towards the close of his discourse, Dr. Tyndall observes : — 

 "The 0rigi?tation of life is a point lightly touched upon, if at 

 all, by Mr. Darwin and Mr. Spencer. Diminishing gradually 

 the number of progenitors, Mr. Darwin comes at length to one 

 ' primordial form ; ' but he docs not say, as far as I remember', 

 how he supposes this form to have been intrDduced. He quotes 

 with saiisfaction the words of a celebrated author and divine who 

 had ' gradually k.irnt to see that it is just as noble a conception 

 of the Deity to believe He created a few original forms capable 

 of self-development into other and needlul forms, as to believe 

 that He required a fresh act of creation to supply the voids 

 caused by the action of His laws.' What Mr. Darwin thinks of 

 this view of the introduction of life I do not know. Whether he 

 does or does not introduce his ' primordial form ' by a creative 

 act, I do not know. But the question will inevitably be asked, 

 'How came the form there?' .... We need clearness and 

 thoriiughness here," &c. Now, I submit that although this is a 

 question which must "inevitably be asked," it is neverthe- 

 less a question with which Mr. Darwin has nothing whatever to 

 do. The problem conceniing the origin of life is as distinct from 



