June 17, 1875J 



NATURE 



125 



conditions of society," This possible theory, he says, "has 

 been made a subject of not less careful study and reflection than 

 the system itself." But after a patient analysis and comparison 

 of its several forms, he comes to the conclusion that it is insuffi- 

 cient to account for the facts. 



Thus, as it seems to me, he clearly repudiates the theory of 

 spontaneous growth. 



Mr. Morgan thinks that his solution of the problem of rela- 

 tionships must have escaped my notice, because I did not discuss 

 it in my paper read before the Anthropological Institute ; but in 

 that memoir I quoted from the chapter in question, and went on 

 to say — 



' ' Mr. Morgan admits that systems of relationships have 

 undergone a gradual development, following that of the social 

 condition ; but he also attributes to them great value in the 

 determination of ethnological affinities. I am not sure that I 

 exactly understand his views as to the precise bearing of these 

 two conclusions in relation to one another ; and I have else- 

 where given my reasons for dissenting from his interpretation of 

 the facts in reference to social relations. " 



Thus I expressly pointed out that Mr. Morgan, while charac- 

 terising the "classificatory " system, to use his own terms, as 

 "arbitrary and artificial," nevertheless also regards it as having 

 "undergone a gradual development following that of the social 

 condition." Surely Mr. Morgan must have written his letter 

 without having my book by him, for it seems to me that the 

 above passages, taken together, represent his own theory, as 

 given in his letter. Mr. Morgan hints that the conclusions con- 

 tained in his last chapter had escaped my notice. He appears 

 to have overlooked the fact that I quoted from that very chapter. 

 I was not, however, reviewing his work, and differing funda- 

 mentally, as I do, from the conclusions adopted by him, while 

 feeling deeply also the great obligations to him under which 

 ethnologists lie, I preferred to state my own views rather than 

 to dwell on the differences between the conclusions at which he 

 and I have arrived. John Lubbock 



Down, Kent, June 7 



Attraction and Repulsion caused by Radiation 



I DID not intend to reply to Prof. Osborne Reynolds' letter 

 in Nature, vol. xii, p. 6, but some persons expect me to say 

 something about it. If the Professor would be careful not to 

 answer me with the' ideas that occur to him as he is " on the 

 point of sending off the paper" (see Phil. Mag., Nov. 1874), 

 he would save himself the trouble of many explanations. After 

 my thousand experiments it is scarcely respectful to try to over- 

 come all by his few, and, after three years of my thought, rather 

 hasty to tell me that he explained it all so suddenly with perfect 

 certainty, and that I am unable to comprehend him. It is also 

 scarcely wise to lead us to infer that probably he cannot explain 

 the whole, but that he knows somebody who will soon do it. 



Prof. Reynolds seems to base his calculations on some of my 

 experiments which dealt with a perceptible amount of gas, and 

 has not taken notice of those where there is no amount of gas 

 known to be present ; for example, in a chemical vacuum. 



Prof. Reynolds must show that there is gas or vapour re- 

 maining, and he must also show that there is enough to produce 

 the mechanical results. He tells us that the forces vdll increase 

 as the density of the gases diminishes. The speed will, but if 

 the force does, that can only be up to a certain point, when it is 

 equally certain that a change will take place, and the motion of 

 the particles or molecules will be attended with less force accor- 

 ding as they diminish in number. The opposite to this involves 

 something not intended. I suppose he does not intend to speak 

 of forces without matter. The analogy with sound is not quite 

 happy, as that is so readily diminished by lower pressure ; al- 

 though the speed is the same, the power is small. Besides this, 

 what will he say to the case where there is no heat and only 

 light ? I am abundantly willing to allow molecules and forces, 

 but I see no place for such as I have beenacquainted with. 



I am working at the subject and shall be glad to come to a 

 true conclusion. Scientific men need not be so very much afraid 

 of a new law of nature, for some are wanted, and there are cer- 

 tainly many yet waiting to be discovered before nature becomes 

 intelligible to us. 



I by no means deny that the phenomena are connected with 

 molecular movements, but I believe that Prof. Reynolds has 

 neither explained this nor proved it by experiment. His expla- 

 nation suits only a part of my work ; and so does the saying that 

 the "experiments stand in much the same relation to the kinetic 



theory of gases that Foucault's pendulum occupied with regard 

 to the rotation of the earth." This is an analogy showing much 

 acuteness, viewing the matter from what I consider the unproved 

 side. 



Prof. Reynolds goes far when he says that my experiments 

 are " the only direct proof that has ever been obtained of the 

 kinetic theory of gases." It may be, but if so, physicists must 

 have been too easily pleased with their theories. 



I might .say much more, but I prefer to wait. There is but 

 little good done by short notes when such a large and important 

 subject waits for elucidation, William Crookes 



London 



American Indian Weapons 



The Pai-ute weapon, described by Mr. Mason in your last 

 number (p. 107), although extremely interesting and quite new to 

 me, appears scarcely sufficiently characteristic of a war weapon 

 to form an exception to the statement of Schoolcraft, that the 

 clubs of the North American Indians as a rule are curved. It 

 would be interesting if it could be ascertained how such a peculiar 

 instrument as that described by your correspondent came to be 

 used as a weapon of war. Its form precludes the possibility of 

 its having been designed for such a purpose. The mode of 

 holding it suggests the idea of its having originally been used as 

 a pounder, the thick end having perhaps been employed for 

 pounding grain, beating out grass for cloth, or for preparing 

 skins. It somewhat resembles the instrument used for making 

 bark cloth in some of the Polynesian Isles, and it corresponds to 

 the Beatle (Battelle) still used by Irishwomen for beating flax, 

 and occasionally, I have no doubt, as a weapon of war ; but 

 these are used with the flat side, not the end. The only weapon 

 I know of that is used like the Pai-ute club is the New Zealander's 

 Merai or Pattoo-Pattoo, the sharp end of which is thrust 

 into the back of the head of the offender; and I have 

 suggested elsewhere that this peculiar and awkward mode of 

 using it arose from its having been originally what its form 

 resembles, a stone axe blade (celt), used as the Australians now 

 use it sometimes, in the hand without any handle. The 

 sharp edge at the end of the Merai shows its original inten- 

 tion, in the same way that the flat end of the Pai-ute club could 

 never have been designed as an offensive weapon, but would 

 have been useful as a pounder ; it may be, in fact, a " survival " 

 converted to other uses. There exists, of course, no law of 

 nature to prevent North American Indians from using straight 

 clubs as well as curved ones, but my observation of their 

 weapons confirms the statement of Schoolcraft, that as a rule they 

 do not. Amongst races in a more primitive state of culture, as 

 amongst the Australians, we find that nearly every form of club 

 that is made straight is used also in a curved form, the curvature 

 arising merely from the natural bend of the branch out of which 

 it was constructed ; when these natural curves were found useful, 

 they appear to have been retained and systematised. But the 

 North American weapons are of a more advanced and conven- 

 tionalised description, and we cannot trace their origin and 

 grnvth so clearly as amongst lower savages. The description ot 

 the Moquis boomerang by Mr. Mason is an interesting fact, 

 which, combined with the mention of it by Bancroft amongst 

 the Pueblo Indians of New Mexico, points to the probability of 

 a connected area of distribution. Drawings of weapons such as 

 those given in your journal are of the utmost value in assisting 

 to trace the distribution of like forms. A, Lane-Fox 



Guildford, June 12 



Hardened Glass 



Perhaps the following short and preliminary account of some 

 observations on the optical and mechanical properties of De la 

 Bastie's toughened, or, as I think more correctly, hardened glass, 

 may interest your correspondent Mr. James H. Logan (vol. xii. 

 p. 87). 



Immediately after the publication of M. Dela Bastie's specifica- 

 tion I prepared specimens of the glass, I submitted them to 

 careful optical examination by polarised light. Perhaps the best 

 experiments are those made by means of short cylinders and 

 small cubes and parallelepipeds carefully "hardened." A small 

 cube with half-inch sides thus prepared has its sides ground 

 plane and polished. The operation of polishing may be dis- 

 pensed with if a small microscopical thin cover be cemented on 

 the ground surface with Canada balsam. The cube is then 

 mounted between strip^f blackened cork, and examined in the 



