232 



NATURE 



yjan. 2 2, 1874 



pound radicles are nearly always multiples of one another, and 

 their magnitude is sufficient to establish the complexity of the 

 radicles themselves. 



The combinations of the same order formed by the simple 

 radicles have all of them nearly the same atomic heat, as the 

 observations of Naumann and Regnault have shown. On the 

 contrary, combinations of the same order formed by a series of 

 analogous compound radicles exhibit specific heats which tend 

 to increase proportionally with the variation of their atomic 

 weights. This, which is precisely the opposite of the relations 

 which would have been supposed to exist between compounds 

 of the same order at the time of Naumann's researches on the 

 identity of the specific atomic weights of the carbonates and 

 sulphates, is another proof of the complexity of these radicles. 



To sum up, the study of the specific heats established by the 

 most recent researches, tends to prove that there is a positive 

 characteristic which, it seems to me, distin:.;uishes the elements of 

 modem chemisti7 from its compounds, and shows that no known 

 compound body ought to be considered as of the same order as 

 an actually simple one. The importance of such a characteristic 

 cannot be doubted, and it becomes greater on account of the 

 mechanical meaning which modern theories ascribe to specific 

 heat. This I feel bound to put in evidence. 



Nevertheless, and I ask permission to return once more to this 

 point, exaggerated conclusions must not be drawn from such 

 an opposition between the mechanical and physical charac- 

 teristics of our simple and compound bodies. 



If our elements have not as yet been decomposed and appear 

 not to be decomposable by tlie forces which are at present at the 

 command of the chemist, and which, as IVI. Dumas at the time of 

 his discussion with Despretz justly remarked, have been so often 

 tried in vain, nothing compels us to assert that they are not 

 decomposable in another way than our compounds are ; as, for 

 instance, as Mr. Lockyer asserts, by means of the forces acting 

 in cosmical space. Nor does anything prevent the supposition 

 that such a discovery as that of voltaic electricity would enable 

 the chemists of the future to overpass the limits which are 

 imposed upon us. 



The possible fundamental identity of the matter constituting 

 our elements, and the possibility of transmuting into one an- 

 other the so-called elements, can moreover be admitted into 

 the category of more or less plausible hypotheses without it 

 necessarily resulting that tliere is a single really existing matter 

 of which our actual elements represent unequal states of con- 

 densation. In fact nothing compels us to conceive the existence 

 of a final decomposition which shall tend necessarily to reduce 

 our elements either to more simple bodies, from the addition of 

 which they arise, or to multiples of a single elementary pon- 

 derable unit. The various states of equilibrium under which 

 the fundamental matter manifests itself would exhibit certain 

 general relations to each other analogous to those which exist 

 between the multiple values of the same function. According 

 to this hypothesis, an elementary body could be broken up 

 without being destroyed in the ordinary meaning of that word. 

 At the moment of its destruction it would suddenly change into 

 one or more simple bodies identical with, or analogous to, 

 our elements. But the atomic weights of the new elements 

 would not show any simple relation to the atomic weight of the 

 element which had by its metamorphosis produced them, the 

 absolute weight alone would remain unaltered throughout the 

 catena of changes. 



But I do not wish to insist further on this hypothesis oi a 

 matter fundamentally identical, although multiform in its appear- 

 ances, and characterised in each one of them by a peculiar mode 

 of motion, such, in fact, that no single one of them can be defi- 

 nitely considered as the starting-point of all the others. Never- 

 theless, we shall only be too glad if Mr. Lockyer, guided by 

 stellar spectral analysis, succeeds m shedding a new light upon 

 these hypotheses, and continues to investigaie questions which 

 M. Dumas raised forty years ago in a book which has contributed 

 so much to our scientific education. „ R. J. r . 



W^ 



SCIENCE IN LIEGE 



JIL have received a somewhat bulky volume of Memoirs of 

 the Royal Society of Science in Liege (1873), m which a 

 considerable variety ot subjects comes under notice ; zoology and 

 mathematics being, perhaps, the most largely represented. 



An t'/ogc; by Prof. Morrcn, on Jean Theodore Lacordaire{«ho 

 died in 1870), is a,ccompanied with a good portrait of that emi- 



nent naturalist. Lacordau-e was originally destined for the law, 

 which, however, he left for commerce. Going out to South 

 America in a business capacity, his bias for natural research was 

 quickly developed, and he commenced those labours to which his 

 after life was devoted. In 1835 he became professor of zoology 

 at Liege, where he continued tdl his death. Lacordaire was a 

 voluminous writer, but his s/immiim opus is the Genera des Co- 

 lio/'teres, which is remarkable for the minuteness of its details 

 and its rigorous truthfulness. 



For some years past we have heard a great deal about the ser- 

 vices which birds render to agriculttne by destroying injurious in- 

 sects. The sentiment is widespread, and vigorous measures of 

 bird protection have been taken in various countries of Europe. 

 M. Edouard Penis here brmgs forward a somewhat opposite 

 view, which he supports by many curious facts Irom a long expe- 

 rience of country life. His position is, briefly, the following : — 

 I. Birds are congregated- in considerable numbers only in the 

 migration time in autumn and spring, when insects are very 

 much less numerous than in the fine season. The rest of the 

 time they live in pairs, sparsely distributed, and rare in cultivated 

 parts, while the insects come forth 01 masse to do their mis- 

 chievous work. 2. Birds destroy insects largely, but these in- 

 sects are, in great part, indifferent, others are eminently useful ; 

 and the really hurtful species destroyed are in very small pro- 

 portion to the whole. Thus the birds do us little service ; and 

 they often do injury in destroying our carnivorous and parasitic 

 insects, as well as attacking fruits and seeds. 3. The insects we 

 have most to complain of are, some of them, big enough to brave 

 the birds, others are too small to attract them; others prove dis- 

 agreeable as food ; many are nocturnal in habits, or, by their 

 immobility, escape notice ; some live underground, or in houses ; 

 and all have an astonishing fecundity which is quite baffling to 

 human resources. 4. Larvos and caterpillars, which do the most 

 damage, live nearly all concealed under ground, under bark, in 

 the deep parts of wood, in the roots of plants, in fruits, in in- 

 habited places, &c., and furnish little tribute to the birds. Those 

 which develop in open air are generally provided with hairs 

 which protect them ; some are nocturnal, some are extremely 

 small. All these facts, in the author's opinion, should greatly 

 modify the ordinary view as to the utility of birds in agriculture, 

 lie points out that certain natural influences tend to preserve an 

 equilibrium in the insect world ; such are, famine occasioned by 

 the too great multiplication of individuals, meteorological pheno- 

 mena adverse to their growth or metamorphosis, and the abun- 

 dant production of jiarasites. M. Ferris does not find fault with 

 measures of bird protection, but objects to the undue merit which 

 is assigned to birds. He urges upon farmers the importance of 

 exercising more discernment in their destructive measures, and of 

 respecting many animals they often regard as nuisances, such as 

 hedgehogs, snakes, lizards, toads, &c. 



Medical men will doubtless be interested in two teratological 

 observations communicated by Dr. Eugene Charlier. One is that 

 of a child rnferiorly double, or a double ileadelphous monster. 

 It is a kind of monstrosity of which Is. Geoflrey Saint-Hilaire 

 supposed the existence, but of w'hich he did not know any au- 

 thentic case. The other monstrosity is a new variety of pygo- 

 melian chicken ; the animal has two accessory limbs joined to 

 the normal wing and leg on one side. The forms are represented 

 in plates annexed to the notes in question. 



An important mathematical paper by M. Brasseur, furnishes 

 a ' * new exposition of the principles of the differential and inte- 

 gral calculus." The following sentences from a commendatory 

 preface by M. Folie, will give some idea of the point of view 

 which the author adopts. "Of all the modes of considering the 

 differential calculus, we do not know of any more philosophical 

 than that of Ivewlon ; but it requires, to be properly understood, 

 a mind well trained to metaphysical speculations. We have, 

 indeed, known good analysts who never grasped it, though they 

 had studied at the best sources. The great difficulty of the dif- 

 ferential calculus is that it attempts to analyse the idea of con- 

 tinuity ; it seeks to express how a function passes in a continuous 

 manner from one state to another ; and it is this passage which 

 has given rise to tlie contradictory idea of the infinitely little, to 

 the indirect idea of limits, and to the philosophic idea of Newton. 

 Brasseur has avoided this great difficulty ; he has succeeded in 

 rendering the method of La Grange, who only employs finite 

 analysis, as convenient in its applications, and as rigorous, as that 

 of limits or of fluxions. We will even say that his method has, 

 from the educational point of view, tlie advantage, over that of 

 fluxions, of not requiring any metaphysical notion ; and, over that 



