AKSENIC, ANTIMONY, BISMUTH. COPPER AND LEAD. 257 



senic, but somewhat deeper black in color. The methods 

 of distinguishing between arsenic and antimony, however, 

 belong to works on analytical chemistry. You can easily 

 see, however, that when a chemist is called upon to deter- 

 mine whether a person has been poisoned by arsenic or 

 not, the chemist must be very careful not to mistake anti- 

 mony for arsenic, for antimony, as you will learn in 363, 

 is a component of tartar emetic, which is sometimes given 

 to produce vomiting when poisoning is suspected. 



361. Arsenical Pigments. Arsenious acid in combina- 

 tion with copper makes several splendid green pigments. 

 Scheelds Green is an arsenite of copper formed by adding 

 an alkaline solution of arsenious acid to a hot solution of 

 copper sulphate. Paris Green is nearly the same, but con- 

 tains acetate of copper also. This brilliant color is exten- 

 sively used as a pigment. It is a very poisonous substance, 

 and its use is dangerous. "It may even prove danger- 

 ous," Stockhardt says, " as a green paint for rooms, since, 

 under some circumstances, volatile combinations of arsenic 

 are formed from it and mix with the air." 



Brunswick Green is another arsenical pigment, prepared 

 like Scheele's Green, only some cream of tartar is added to 

 the copper sulphate, and some slaked lime to the arsenious 

 solution. The facility with which compounds of arsenic 

 can be obtained by the common people, and their cheap- 

 ness, is much to be deplored. 



362. Antimony. This metal is not so well known as one 

 of its salts called tartar emetic ; and yet in some of the arts 

 it is largely used. It is one of the constituents of type- 

 metal. The alloy of lead and antimony which we have in 

 type-metal at the moment that it becomes solid in casting 

 expands, so that the mould is well filled out, and the type 

 is therefore complete, with well-marked lines and angles. 

 But neither of these metals when alone makes a good cast- 



