SIR B. C. BRODIE ON THE CALCULUS OF CHEMICAL OPERATIOXS. 827 



The preceding Tables comprise a large number of the ascertained combinations of the 

 prime factors to which they relate, and afford sufficient illustration of the method. 

 Hereafter I shall limit myself, in the case of each factor, to a few examples. 



With regard to the selection of letters by which the symbols of simple weights may 

 be expressed, it is a mistake to confuse the objects of a symbolic system with those of a 

 " memoria technica," and I am inclined to believe that a purely accidental distribution 

 of letters among the weights to be expressed would be the best. In the selection here 

 made, however, I have not proceeded rigidly upon this principle, a certain reminiscence 

 of the name being retained in the symbol, as for example, the ^ of o^vc, the d of Oelov, the 

 X of -^^Xiopoc, and the S of i^papyvpoc. Facility of writing and reading the symbols is, 

 however, far more important than any aid to memory which can be thus aflForded, and 

 these points are to be mainly considered. The unit of hydrogen, which occupies a 

 peculiar position as the " modulus " of the system, is indicated by a special symbol, a. 

 With regard to names, I cannot pretend to be more successful than others. In the 

 confusion which at present prevails on this point it is almost impossible to use a 

 language which shall be universally understood, new names having been frequently and 

 inconsiderately assigned to chemical substances as the expression of some transitory 

 theory, or even individual speculation, rather than to fulfil the main purpose of words, 

 as the common medium for the exchange of ideas. Hence, as in the language of 

 barbarous tribes* and from causes similar to those which there prevail, the same object 

 comes to be denoted by a variety of appellations, and chemists of different schools can 

 hardly understand one another. It is to be hoped that, as the science gradually 

 assumes a more exact form, the use of symbols will enable the chemist to dispense, to a 

 great extent, with any other nomenclature, and afford a satisfactory solution to this 

 difficult problem. 



Group 2. — Symbols of Carhon, Silicon, and Boron. 



(1) Symbol of Carbon. — ^Although the density of the vapour of carbon has never been 

 determined by experiment, we are yet able to construct numerous chemical equations 

 which connect the vapour-density of carbon with known vapour-densities, and in which 

 the number of volumes of carbon-vapour which enters into the chemical equation 

 appears as an indeterminate quantity. From these equations we are able to determine 

 with a high degree of probability, though doubtless only by the aid of hypothesis, the 

 symbols of many gaseous compounds of carbon, the prime factor of carbon, and, within 

 certain limits, the symbol of the element itself. 



It is known from experiment that marsh-gas can be decomposed into hydrogen and 

 carbon, and that the number of volumes of hydrogen formed in this decomposition is 

 twice the number of volumes of marsh-gas decomposed. 



• " Any feature that struck the ohserving mind as peculiarly characteristic could be made to furnish a new 

 name. In common Sanskrit dictionaries we find five words for land, 11 for light, 15 for cloud, 20 for moon. 

 &c." — Mai MtLLEK, ' Lectures on the Science of Language,' Ed. v. p. 426. It would be easy to find parallel 

 examples in the nomenclature of chemistry. 



