130 SPECIAL METHODS OF AJ^ALYSIS. 



main witli that of Zettnow. {Poggendorf s Annalen^ 

 103, 324.) 



The attention of the analyst is called to Table X, 

 where the average and extreme composition of agricul- 

 tural materials and j^roducts are given ; by consulting 

 this table he can ascertain what he may expect to find in 

 any substance under examination, that is used in, or 

 produced by, agriculture, and whether or not he must 

 needs work with special care, or with large quantities of 

 the substance, in order that a small quantity or traces of, 

 any element or compound shall not escape detection. 



A. 



DETECTION OF ACID ELEMENTS AND ACIDS. 



1. a. The substance is a solution ; this solution will 

 be referred to as \h^ first solution, - - - - 6 

 h. ISTot a solution. - - - - - - 2 



2. a. The substance is soluble in water, or in dilute 

 or concentrated nitric or hydrochloric acid ; this 

 solution will be referred to as \}\q first solution, - 6 



b. It is partially soluble in water or acids, as indi- 

 cated by the residue left undissolved even after 

 heating, and by the distinct residue left on evapo- 

 ration of a drop of the solvent with which the 

 substance has been treated. Treat a larger portion 

 of the finely divided substance with another por- 

 tion of the solvent, filter, and mark the filtrate F 2. 

 With the contents of the filter go to - - - - 3 



c. It is quite insoluble in water or acids. - - - 3 



3. A portion of the insoluble substance, in the shape 

 of a very small fragment, if possible, rather than 

 a fine powder, is fused for a considerable time in a 

 bead of j^hosphorus-salt on platinum wire ; the 



