212 Jjioifraphif of Berzelhin. 



ments must correspond with the simple atoms. Moreover, 

 since it appears to have been proved, by often -repeated ex- 

 periments with organic bodies, that their hydrogen can be 

 replaced by an equal volume of chlorine, a simple, and not a 

 double, atom of hydrogen must be able to replace one atom 

 of oxygen or sulphur. 



Even if it does sometimes happen that we not find conclu- 

 sions of this kind confirmed by experience, if in the replace- 

 ment of one body by another in compounds, an element, as 

 for instance potassium, may be replaced by a compound 

 radical such as ammonium, still it is not admissible to 

 assume that such substitutions as may be theoretically in- 

 ferred from the similarity in atomic weight, or atomic vo- 

 lume, really do take place, without the authority of repeated 

 experiment. It is certainly convenient to regard equivalent 

 and atom as synonymous terms, although not truly appro- 

 priate in a scientific view. d^ihxiiao'i eiom aifi «jjw alodm^a 



For the purpose of expressing the proportions in which 

 bodies combine chemically, Berzelius, so early as the year 

 1815, employed certain signs as symbols for the different 

 elements; Such signs were employed long before this in 

 chemistry, or rather alchemy, although they were then of 

 little value. These symbols undoubtedly owed their origin 

 to the mysterious relation between planets and metals as- 

 sumed by the alchemists, and the pleasure which they took 

 in expressing themselves in a manner unintelligible to the 

 people. Berzelius would not adopt the old symbols, not 

 only because they were, in fact, destitute of all significance, 

 but likewise because it is certainly easier to write the ab- 

 breviation of a word than to draw a figure. The symbols of 

 Berzelius, however, serve to express the chemical combining 

 proportions, and the chemical formulae furnish a means of 

 representing the numerical results of an analysis witli all 

 the simplicity of an algebraical formula. 



The system of symbols introduced by Berzelius has met 

 with such universal recognition, on account of its extraor- 

 dinary convenience, that there is probably no chemist who 

 does not now employ it ; and this renders it the more remark- 

 able, that the opposition made to this innovation was at first 



