SANGER AND GIBSON. — DETERMINATION OF ANTIMONY. 733 



As to the delicacy of the process in the detection of minimal amounts 

 of antimony, a mirror corresponding to 0.005 mg. can be detected and 

 identified with certainty. With 0.001 mg. a faint deposit is seen. Yet 

 the differentiation of amounts under 0.01 mg. presents some difficulty. 

 Possibly the solution of the problem of how to sensitize the zinc prop- 

 erly in the Marsh process as applied to arsenic will enable one to 

 detect smaller amounts of antimony with certainty. The question of 

 the delicacy of the process has not so much concerned us, however, 

 as its practicability. Its application to the determination of small 

 amounts must of course be worked out for each particular problem. 

 This does not come, however, within the scope of the present investi- 

 gation, but certain applications of the method are under consideration 

 in this laboratory. 



Harvard University, Cambridge, Mass., 

 January 1, 1907. 



