214 ANNUAL OF SCIENTIFIC DISCOVERY. 



position which it at present occupies. The comparative unanimity which 

 prevailed before the time of Gerhardt's was the unanimity of submission 

 to authority; but the greater unanimity which now prevails is the unan- 

 imity of conviction, consequent upon an intermediate period of solitary 

 insurrection by general disturbance and ultimate triumph. Bearing in 

 mind how much the origin of the new system by Gerhardt, and its com- 

 pletion by his colleagues and disciples, owe to a correct appreciation of the 

 harmony subsisting between chemical and physical relations, we cannot but 

 give a hearty welcome to any large exposition of mixed chemico-physical 

 phenomena; and whether or not we agree with all his conclusions, there 

 c.ui be but one opinion as to the obligation chemists are under to Prof. 

 Kopp, of Giessen, for the great addition he has recently made to our 

 knowledge and means of obtaining a further knowledge of what has 

 hitherto been but a very limited subject, namely, specific heat. The 

 agreement of chemists as to the elemental atomic weights is tantamount 

 to an agreement among them as to the relative quantities of the different 

 kinds of matter which shall be represented by the different elemental 

 symbols ; and this brings me to the subject of chemical notation. At one 

 time many chemists even of considerable eminence believed and taught 

 that Gerhardt's reformation had reference mainly to notation, and not to 

 the association and interpretation of phenomena, and it became rather a fash- 

 ion among them to declaim against the puerilities of notational questions. 

 That the idea is of far greater importance than the mode of expressing it, is 

 an obvious truism ; but nevertheless the mode of expression has an impor- 

 tance of its own, as facilitating the spread of the idea, and more especially 

 its development and procreation. It has been well asked, in what posi- 

 tion would the science of arithmetic have been but for the substitution of 

 Arabic for lioman numerals, the notation in which value is expressed by 

 the change in position for that, in which it is expressed mainly by the 

 repetition of a few simple signs? It is unfortunately too true that chemical 

 notation is at present in any thing but a satisfactory state. The much- 

 used sign of addition is, I conceive, about the last which would be deliber- 

 ately selectt d to represent the fine idea of chemical combination, which 

 seems allied rather, I should say to an interpenetration than to a coarse 

 apposition of atoms. The placing of symbols in contiguity, or simply 

 introducing u point between them, as indicative of a sort of multiplication 

 or involution of the one atom into the other, i-^, I think, far preferable j 

 but here, as pointed out by Sir John Iferschcl, \\c violate the ordinary 

 algebraic understanding, which assigns very different numerical value to 

 the expressions x y and x X y respectively. I know, indeed, that one 

 among us has been engaged for some years past in conceiving and 

 working out i new and strictly philosophical system of chemical notation, 

 by means of actual formula?, instead of mere symbols ; and I am sure 

 that I only < xpress the general wish of the Section, when I ask Sir Ben- 

 jamin Brodiij not to postpone the publication of his views for a longer 

 time than is absolutely necessary for their sufficient elaboration. In any 

 case, however, the symbolic notation at present employed, with more or 

 less modification of detail, must continue to have its peculiar uses as an 

 instrument of interpretation, and it becomes therefore of importance to 

 us to render it more precise in meaning and consistent in its application. 

 Many of its incongruities belong to the very lowest order of convention ; 

 such, for example, as the custom of distinguishing between the represen- 



