440 



NATURE 



{{Sept. 16, 1875 



do more than any centralised scheme for the promotion of che- 

 mical research. 



To the advancement of chemistry by the formation of public 

 opinion on the questions of scientific education and the endow- 

 ment of original research, the Chemical Section of the British 

 Association may reasonably hope to contribute. But doubts 

 have been expressed as to the serviceableness of this or any such 

 organisation ior the direct advancement of our science itself. No 

 doubt we cannot accomplish much. Chemical inquirers at the 

 present time may be compared to a party of children picking 

 wild flowers in a large field : at first all were near together, but 

 as they advanced they separated, till now they are widely scat- 

 tered, singly, or in groups, each busy upon some little spot, 

 while for every flower that is gathered ten thousand others remain 

 untouched. 



That the science of chemistry would advance more rapidly if 

 it were possible to organise chemists into working parties, 

 having each a definite region to explore, cannot, I think, be 

 doubted. Is such organisation in any degree possible ? 



The experiments of which Bacon has left a record, though 

 curious historically, have no scientific value. But in one respect 

 his ' ' Physiological Remains " furnish an example which we 

 might follow with profit. "Furthermore," he writes, "we pro- 

 pose wishes of such things as are hitherto only desired and not 

 had, together with those things which border on them, for the 

 exciting the industry of man's mind. " I will quote further, as 

 an example, a part of one of his "wishes," which has very 

 recently been fulfilled. " Upon glass four things would be put 

 in proof. The first, means to make the glass more crystalline. 

 The second, to make it more strong for falls and for fire, though 

 it come not to the degree to be malleable." 



I do not know that the industry of M. de la Bastie's mind 

 was excited by Bacon's mention of glass more strong for falls and 

 for fire among things hitherto only desired and not had ; but the 

 conception ot such an enumeration seems to me worthy of its 

 author. Much fruitless and discouraging labour might be saved, 

 a stimulus might be given to experimental inquiry, and chemical 

 research might become more systematic and thus more produc- 

 tive, if Bacon's example were followed by the leaders of chemistry 

 at the present day. 



The Council of the Pharmaceutical Conference, whose meeting 

 has just preceded our own, has published a list of subjects for 

 research which they commend to the attention of chemists. 

 Where one of these subjects has been undertaken by any chemist 

 his name is appended to it. Might not the representatives of 

 scientific chemistry issue a similar list? 



Perhaps two or three of the distinguished English chemists 

 who are members of this Association might be willing to serve 

 on a committee which should put itself into communication with 

 the leaders of chemical inquiry abroad, and should make and 

 obtain and publish suggestions of subjects for research. Such a 

 list so got together would, I think, find a welcome place in all 

 scientific journals, and would thus be widely known and easily 

 accessible to every student. 



That which chiefly makes the organisation of chemical inquiry 

 desirable is the boundless extent of the field upon which we have 

 entered. Not tvery fact, however laboriously attained and 

 rigorously proved, is an important fact, in chemistry any more 

 than in other branches of knowledge. Our aim is to discover 

 the laws which govern the transformations of matter ; and we 

 are occupied in amassing a vast collection of receipts for the pre- 

 paration of different substances, and facts as to their composition 

 and properties, which may be of no more service to the general- 

 isations of the science, whenever our Newton arises, than were, 

 I conceive, the bulk of the stars to the conception of gravitation. 



It may, however, be urged that the growth of chemical theory 

 keeps pace with the accumulation of chemical facts. It is so, if 

 the elaboration of constitutional formulse is leading us up to such 

 a theory. But at present, however useful and ingenious this 

 mode of summarising chemical facts may be, it does not amount 

 to a theory of chemistry. 



Two objections to regarding $uch formulse 'as anything more 

 than a chemical short-hand, as it has been termed, seem worth 

 recalling. The first is mentioned at the outset in most text- 

 books in which these formulEe are employed, but sometimes, I 

 venture to think, lost sight of afterwards. The arrangement of 

 the atoms of a molecule in one plane is equally convenient in 

 diagrams, and improbable as a natural fact. But is not this 

 arrangement used as though it were a natural fact when the pos- 

 sible number of isomeric bodies is inferred from the number of 

 different groupings of the atoms which can be effected on a plane 



surface ? The conceptions of plane geometry are much simpler 

 than those of solid geometry (which is another recommendation 

 of the present system of formulae) ; but so far as I am able to 

 follow the similar theories which have recently been propounded 

 independently by MM. Le Bel and van't Hoff, the consideration 

 of tlie possible isomerisms of solid molecules leads to new con- 

 clusions.* Wislicenus has found that paralactic acid undergoes 

 the same transformations as ordinary lactic acid when heated and 

 when oxidised. The two acids differ in their action on polar- 

 ised light. His conclusion is that paralactic acid does not differ 

 in its atomic structure from the lactic acid of fermentation, and 

 that the kind of isomerism which exists between the two acids 

 is not connected with the difference in the reciprocal arrangement 

 of the atoms, but rather with a difference in the geometric 

 structure of the molecule. To this difference he gives the name 

 of "geometric isomerism. "t The authors named above agree 

 in supposing that the action of substances in solution on polarised 

 light results from an unsymmetrical arrangement of atoms and 

 radicles in three dimensions around a nucleus-atom of carbon. 



The second objection relates to the statical character of the 

 account which "developed" formula; give of the differences 

 between different kinds of matter. The modern theory of heat 

 supposes, not only that the molecules which constitute any por- 

 tion of matter are in constant rapid motion, but that the atoms 

 which constitute each molecule are similarly moving to and 

 fro. Such movement might be an oscillation about the position 

 assigned to the several atoms in the constitutional formula of 

 the molecule. Since, however, the modes of formation and de- 

 composition of substances are the principal facts upon which the 

 formulae are based, it is to be considered whether these facts may 

 not depend altogether upon the nature or average nature of the 

 motion impressed upon the atoms — that is, upon dynamical and 

 not upon statical differences. 



Many substances are known whose existence is contrary to 

 the theory of valency and saturation, such as nitric oxide and 

 carbonic oxide ; others, which transgress the theory of isomerism, 

 such as chloride of dichlordibromethane (C^ CP Br^, CI*) and 

 bromide of tetrachlorethane (C^ Cl^, Br^), which should be 

 identical, but are isomeric •.% yet these theories are simply an 

 expression of the statement that certain substances can exist or 

 can differ, while others cannot. It is true that in the vast ma- 

 jority of cases the theoretical limitation seems to hold good. But 

 just as the absence of any fossil remains of the connecting links 

 between species is only significant if the geologic search has been 

 sufficiently thorough, so it is with chemical theories depending 

 upon the non-existence of certain classes of bodies. Indeed, in 

 our case, where investigation is guided by theory, and, as a rule, 

 only those things which are looked for are found, the limitation 

 may be partly of our own making. A chemist who should de- 

 part from the general course, and set himself to prepare substan- 

 ces whose existence is not indicated by theory, would perhaps 

 obtain results of more than the usual interest. 



Among chemical inquiries, if ever such a list as I have ven- 

 tured to suggest should be drawn out, I hope that many would 

 be included relating to the most familiar substances and the 

 simplest cases of chemical change. The thorough study of a few 

 reactions might perhaps bring in more knowledge of the laws of 

 chemistry than the preparation of many new substances. 



I believe that if any chemist not content with a process giving 

 a good yield of some product examines minutely the nature ot 

 the reaction, observing its course as well as its final result, he 

 will find much more for study than the chemical equation repre- 

 sents. He will probably also find that the reaction and its con- 

 duions are of a formidable complexity, and will be driven back 

 towards the beginnings of chemistry lor cases sufficiently simple 

 for profitable study. 



In concluding my remarks, I desire briefly to refer to another 

 branch of chemical science, to the advancement of which this 

 Association seeks to contribute, I mean applied or technical 

 chemistry. One of the principal differences between the papers 

 read before this Section, as a class, and those which the Chemical 

 Society receives, is the larger proportion in our list of papers on 

 technical subjects. Whatever chemists may hold, there can be 

 no doubt that the estimation of our science by the outside world 

 rests largely on the well-founded belief that chemistry is useful. 

 Indeed, though scientific chemists are justly eager to vindicate 

 the value of investigations remote from any application to the 

 arts, they cannot feel a livelier sense of triumph when the suc- 



* Bull, de la Soc. Chem. de Paris, t. xxii. p. 337, and t. xxiii. p. 295. 

 t Ann. Chim. et Phys., s™'^ s6rie, t. 1. p. 122. 

 I Bull, de la Soc. Chim. de Paris, t. xxiv. p. 197- 



