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X. 



ON A COMBINATION OF WET AND DEY METHODS IN 

 CHEMICAL ANALYSIS. Pakt I. By W. E. ADENEY, 

 F.LC, Assoc. R.C.Sc.L, Curator, Royal University of Ireland; 

 and T. A. SHEGOG, A.I.C, Assoc. R.C.Sc.L, Assistant 

 Chemist, Royal College of Science, Dublin. 



[Eead February 18, 1891.] 



Plattner, in his work on the blowpipe/ states that, when the 

 oxides of the metals are fused on charcoal with borax and sodium 

 carbonate in the E. F., some are reducible, and some non-reducible, 

 to the metallic state ; and he has suggested a general scheme for 

 the analysis of minerals based upon the possibility of separating 

 the reducible from the non-reducible oxides, when so treated. 

 Plattner's scheme involves the employment of wet as well as dry 

 methods of analysis. About 1 decigram of the substance is mixed 

 with about 1 part of fused borax and 1 of sodium carbonate ; 

 the whole is wrapped in a little cylinder of soda paper, and fused 

 hefore the blowpipe in a hole on charcoal. As the quantity of 

 reducible oxides is usually too small to obtain them in a single 

 bead, about 1 decigram of metallic silver or gold should be 

 added, in the form of a button, to take up the reduced metal as it 

 is formed. In this way it is stated that a preliminary separation 

 of the reducible from the non-reducible oxides may be effected. 

 The reducible oxides are said to be those of the following metals : — 

 arsenic, antimony, silver, mercury, copper, bismuth, thallium, 

 lead, tin, zinc, indium, cadmium, and nickel. The volatile metals 

 escape, either partially or wholly, during the fusion. The non- 

 reducible oxides are those of the alkaline earths, and of chromium, 

 aluminium, iron, manganese, cobalt (in the absence of arsenic 

 acid, and when not present in too large quantity), molybdenum, 

 tungsten and titanium. 



1 English Edition of Plattner's "Manual of Analysis by the Blowpipe," edited by 

 J. H. Cookesley, pp. 116 ei seq. 



