Atig. lo, 1876] 



NATURE 



32, 



SCIENTIFIC SERIALS 



ZeUsckrift der Oesterreichischen Gesellschaft fur Meteorolo^ie, 

 April. — This number contains an article by Signer Denza, direc- 

 tor of the Observatory at Moncalieri, on an inspection by him 

 of observatories of the second order, according to the recom- 

 mendations of the Leipzig and Vienna Conferences, for the 

 correction of barometers. He has found that a safe verification 

 can only be made when all the rules and precautions are ob- 

 served, and recommends that the barometer taken in travelling 

 from place to place should not be too narrow in bore, and 

 should be carefully compared with the standard before and after 

 the journey. — The next article is by Dr. Hann, on the results of 

 observations made by the Swedish Arctic Expedition of 1872 in 

 Spitzbergen and East Greenland, published in Stockholm, The 

 observations are of great value, and deserve the full notice here 

 given them by Dr. Hann. 



Reale Istituto Lombardo di Scienze e Lettere. Rendiconti. 

 Vol. IX. Nos. I, 2, 3 (1876). Among the papers contained in 

 these numbers we note the following : — Singular structure of the 

 leaves in the Empetrocese, by M. Gibelli. — Sketch of Dr. 

 Cantor's recent studies on the history of land-surveying, by M. 

 Schiaparelli. — Researches on the action of oxygen, at the ordi- 

 nary temperature on sulphur, on alkaline and terralkaline sul- 

 phides, and on hyposulphite of calcium, by M. Pellogio. — 

 Report on the vine-disease of Phylloxera, by a Committee of the 

 Institute. — On a new disease of chestnuts, by M. Gibelli. — On 

 the constitution of veratric acid and veratrol, by M, Korner. — 

 On the temperature of flames, by M. Ferrini. 



Gaszeita Chimica Italiana, anno vi., 1876, fasc. iv. — E. Patemo 

 and G. Briosi contribute a paper on hesperidin. These two 

 investigators studied hesperidin derived from the common 

 orange {Citrus aurantium, Risso). About 4,000 ripe oranges 

 were found to yield 180 grammes of impure hesperidin. They 

 experienced much difficulty in their endeavours to purify this 

 substance. — G. Pisati contributes the only two original papers in 

 addition to the one we have already noticed. His first paper 

 details some experimental researches made by the author on 

 electro-static induction. The second treats of the elasticity ot 

 metals at different temperatures. — The remainder of this number 

 is filled up by summaries of the contents of foreign chemical 

 journals, and a review of a book by T. Schutzenberger, " On 

 Fermentation." 



In the Zdtschrift Jilr Wissenschaftliche Zoologie, vol, xxvi. , 

 part 2 (December, 1875), W, Repiachoff continues his contribu- 

 tions on the Chilostomous Bryozoa, giving many interesting par- 

 ticulars about the development of the amphiblastic ovum of 

 Lepralia and Tendra. — Ludwig GrafT describes the anatomy of 

 the Sipunculoid ChcFtoderma nitidulum. — Dr. Hubert Ludwig 

 writes on the interesting Gastrotrichous Rotifers, established as 

 a separate order by Metschnikoff. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, May 18 — " The Calculus of Chemical 

 Operations. — Part II. On the Analysis of Chemical Events," 

 by Sir B. C. Brodie, Bart,, F, R. S,, late Professor of Chemistry in 

 the University of (Oxford, 



Introduction. — An account is here given of the origin of our 

 views of the constitution of ponderable matter, regarded as con- 

 stituted of units compounded of " simple weights," These 

 considerations lead to two systems, and two only, in which the 

 unit of hydrogen is respectively expressed by the symbols a and 

 or. Between the systems we have no absolute means of selec- 

 tion, but a preference is here given to the system a as imme- 

 diately leading to the law of even numbers. 



The exception presented by the binoxide of nitrogen is then 

 considered, and a hypothesis suggested to account for this 

 anomaly. 



The object of the work is then defined — namely, given a 

 chemical event, how are we to determine the events of which it 

 is compounded? 



Section I. — The Question of the Multiplication and Division of 

 Chemical Equations is here considered. It is shown that we may 

 multiply and divide a chemical equation of the form n — o, by 

 any chemical function, if the sum of the numerical coefficients 



in that equation is equal to zero, but otherwise not. A method 

 is given by which every chemical equation may be brought 

 under this form. Such an equation is termed a " normal " 

 chemical equation, for it is an equation on which we may 

 ojSerate by the rules of elementary algebra. 



It is then shown that every chemical expression of the form 

 A {x-a)y-b, and also h.{x-a) {y- b) (^z-c) . . . (that is, the 

 continued product of any number of such factors more than 

 one), necessarily — o. 



As regards the interpretation of normal chemical equations. 

 Normal equations express the identity of the two members of 

 the equation, not only as regards matter, but as regards matter 

 and space also. Thus the equation i + 2a| = 20 + |^ asserts not 

 only that the matter of two units of water is identical with the 

 matter of two units of hydrogen and a unit of oxygen, but also 

 that an empty unit of space and the space occupied by two units 

 of water are identical with the space occupied by two units of 

 hydrogen and a unit of oxygen. 



It is further shown that in any chemical equation any one of 

 the prime factors of the equation may be substituted for another, 

 and the equation will still be true. 



Section II. — Our knowledge of the identity of matter is de- 

 rived from chemical transmutations or events ; and every chemi- 

 cal equation may be regarded as the record of such an event or 

 some number of such events. Chemical events may be regarded 

 as compound or simple. A compound event is defined as an 

 event which is regarded in the system of events under our con- 

 sideration as constituted of two or more events. A simple 

 event is an event which is not so regarded. Thus, for example, 

 take the system of the four events : — 



(1) o?v + Q?K^(i3 = aw + a^K^v, 



(2) a*K^\) + d^K^u = aw + a'^K*v, 



(3) o®K*ii+ a^K^o) = aai + a^K*v, 



(4) a^v + ;^a.^K^w — 300) -)- o.^k'^v. 



The event 4 is a compound event, being the aggregate of the 

 events i, 2, 3 ; whereas the events I, 2, 3 are in that system 

 simple events, being incapable of such a construction. 



Section III. — On the Catises of Events. — The cause of an event 

 is given when the operations are defined by the agency of which 

 the event occurs. Def. If in any chemical event the change in 

 the arrangement of the symbols, by which the composition of 

 the units of matter before and after the event respectively is 

 symbolised, be of such a nature that where in the arrangement 

 before the event the symbol x appears, the symbol a apfears 

 after the event, and where a appears before x appears after, so 

 that the two arrangements differ in this respect and this re- 

 spect alone, then the event occurs by the substitution of a for 

 X, which is the " cause" of the event. Hence the same event 

 may arise from more than one cause. Thus, for example, the 

 event 



Kyx + Kab — Kya + Kxb 



occurs by the substitution of a for x and of b for y, for these 

 symbols satisfy the condition given in the above definition. 



It is similarly shown that the event 

 Kxyz -J- Kabz + Kayc + Kxbc = Axyc + Aabc + Aayz ■{■ Axbz 

 occurs by the substitution of a for x, b for y, z for c ; and, 

 further, that if the equation to any chemical event be of the 

 form A {x - a) {y - b) {z - c) (v - d) {w - e) , . . — o, that event 

 occurs by the substitutions of a for x, b iox y, c for z, d for v, 

 efor w . . . . 



If in these substitutions any symbol, say "a" = i, the event 

 occurs by the transference of the simple weight thus symbolised. 



The following event occurs in three ways by the substitution 

 of I for X, the hydride of propyl, aV, being constant, 



a'K'x^ + 3«'«3|^x = «'«'«' + 3«'«^rX, 

 the equation being of the form 



Similarly the event 



is an event occurring in three ways by the transference of x» the 

 equation being of the form 



aMx-0^ = o. 



I submit the following equation to the consideration of the 

 reader : — 



aV|(;8-|)(a/c2|-i)=o. 



Section IV. Elementary Analysis oj Events. — If the equation 

 {0 a chemical event be capable of expression as the continued 



