V. 



ANALYTICAL CHEMISTRY. 



34. INTRODUCTORY REMARKS AND PRELIMINARY 

 EXAMINATION. 



General remarks. Analytical chemistry is that part of chemistry 

 which treats of the different analytical methods by which substances 

 are recognized and their chemical composition determined. This 

 determination may be either qualitative or quantitative, and, accord- 

 ingly, a distinction is made between a qualitative analysis, by which 

 simply the nature of the elements (or groups of elements) present in 

 the substance under examination is determined, and a quantitative 

 analysis, by which also the exact amount of these elements is ascer- 

 tained. 



In this book qualitative analysis will be considered chiefly, as the 

 methods for quantitative determinations of the different elements are 

 so numerous and so varied that a detailed description of them would 

 occupy more space than can be devoted to analytical chemistry in this 

 work. Some brief directions concerning quantitative determinations, 

 especially by volumetric methods, are given in Chapter 38. Every- 

 one studying analytical chemistry should do it practically, that is, 

 should perform for himself in a laboratory all those reactions which 

 have been mentioned heretofore as characteristic of the different ele- 

 ments and their compounds, and, furthermore, should make himself 

 acquainted with the methods by which substances are recognized 

 when mixed with others, by analyzing various complex substances. 



Such a course of practical work in a suitable laboratory is of the 

 greatest advantage to all studying chemistry, and students cannot be 

 too strongly advised to avail themselves of any facilities offered in 

 performing chemical experiments, analytically or otherwise. 



Apparatus needed for qualitative analysis. 



1. Iron stand. (Fig. 48.) 



2. Bunsen lamp with flexible tube (Fig. 48) or (where without gas-supply) 



spirit-lamp and alcohol. 



371 



