346 Mr. Children's Summary Vieio of [May, 



becomes much more easy by this method, I have thought it right 

 to adopt it."* 



Now really if the symbols are intended " to facilitate the 

 expression of the proportions of the elements of chemical com- 

 pounds, and to enable us to state briefly and easily the number 

 of elementary atoms which any of them may contain/' we can 

 hardly conceive any contrivance less calculated to answer its 

 purpose ! For here in the very same table we have two expres- 

 sions of precisely the same kind, denoting two very different 



sorts of compounds, Al Si, representing the neutral silicate of 



alumina, and Al S a subsulphate of the same base. 



Again Ca^ Si'^ denotes one neutral salt, silicate of lime, and 

 Ca S** another equally neutral compound, sulphate of lime. 



The formula Ca^ Si^ represents, as we have just stated, the 



silicate of lime, and Ca^ Si* the bisilicate ; the acid of the first 

 containing the same number of atoms as the base, and that of 

 the second twice as many, so that these brief and easy statements 

 require the reader to multiply the dots over each letter by their 

 respective exponents, and then compare the ratios of the pro- 

 ducts before he can tell whether the salt be neutral, super-acid, 

 or with excess of base. This indeed is easy enough in the two 

 instances just mentioned, but it will probably require some- 

 reflection before the reader perceives the meaning of Fe^ S* + 



6 Fe S^ + 72 Aq, and finds out that it means sulphas biferroso- 

 ferricus cum aqua. 



The symbols of organic atoms are denoted, like the inorganic, 

 by the respective initial letters of the Latin names of the sub- 

 stances, but are distinguished from the latter by a line drawn 



above the letter. Thus A = acetic acid, C = citric acid, T = 

 tartaric acid, &c. So much for the symbols. That they are on 

 the whole ingeniously contrived we do not mean to deny, but 

 that they are necessary or useful we are much disposed to ques- 

 tion. At all events they should be consistent with themselves, 

 and the anomaly which we have pointed out between the sul- 

 phates and silicates, should, as it very easily might, be done 

 away. If a cypher be required, the key should be con- 

 stant, and apply equally to every part of it ; but there are in our 

 opinion many and serious objections to the adoption of symbols 

 at all. In the first place it requires great care to write them 



* Essai snv la Tlieorie des Proportion!! Chimiques, p. 170. 



