434 MODERN CHEMISTRY. 



on the progress of the science. Pervading every part of the 

 subject, from the simple observation of external physical 

 appearances, to the most complex and subtle forms of ex- 

 periment in the analysis and synthesis of organic bodies, its 

 value is more especially felt in these later and higher opera- 

 tions. The perfection of analysis, in its conjoint relation to 

 qualities and quantities, is in truth the cardinal point of all 

 chemistry. We might give curious contrasted examples of 

 the grossness of this operation fifty years ago, and the exact- 

 ness it has attained at the present day. Whether it were the 

 examination of a mineral water, or a metallic ore, or an animal 

 or vegetable product, the older analysis seldom yielded half the 

 ingredients which are now derived by the chemist from the 

 same material of experiment. The greater number lay hidden 

 under the imperfection of the means used to separate them. 

 It is true that those indicated were generally the most 

 important, and present in largest quantity. But it often 

 happened that the ingredients, thus latent under ruder 

 forms of analysis, were really essential elements in the com- 

 pound; modifying its physical qualities, determining its 

 relation to other chemical agents, or providing for its uses in 

 the economy of nature. Thus what was recorded as loss or 

 undefined result the mere residual dross of ancient analysis 

 has become richly prolific to modern research ; affording 

 those rarer products, which, while they seem to encumber 

 our chemical tables by their number and diversity, do in 

 effect present so many fresh objects of enquiry, and give 

 promise of the disclosure of relations hitherto unknown. 



To refer to particular instances of this great change might 

 detract from what we wish to convey of its universality. A 

 single illustration may be taken from the history of Iodine 

 and Bromine substances discovered some forty years ago in 

 the waters of the sea, and in certain sea plants remarkable 

 as new and elementary forms of matter to our present know- 



