Gooch and Beyer — Use of the Filtering Crucible. 249 



Art. XXIX. — The ZTse of the Filtering Crucible in Electro- 

 lytic Analysis / by F. A. Gooch and F. B. Beyer. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — clxxi.] 



The rapidity with which a metal or oxide may be thrown 

 upon the electrode and thereafter handled successfully in the 

 ordinary processes of electrolytic analysis depends upon keep- 

 ing to conditions under which deposits are compact and adher- 

 ent. It is for the purpose of getting adherent deposits that 

 in modern rapid processes use is made of rotating electrodes,* 

 of apparatus so arranged that gases evolved or introduced 

 shall stir the liquid,f and of the agitating action of a magnetic 

 field.* 



The use of these methods is, however, limited to those cases 

 in which attainable conditions and the nature of the processes 

 are such that the deposits may be handled and washed without 

 loss of material from the electrode. Plainly, the range of 

 conditions and processes may be very much extended if means 

 can be found for handling easily and safely electrolytic 

 deposits more or less loose. The chief purpose of the device 

 to be described, in which the perforated 1 



filtering crucible, of platinum or of por- 

 celain, is adapted to the use of an elec- 

 trolytic cell, is to handle such deposits. 



First Process. 



Figure 1 shows a convenient form of 

 apparatus for use in electrolytic analysis. 

 The crucible (A), fitted in the usual 

 manner with an asbestos felt (a), serves 

 as an electrode (e) the surface of which 

 is very much increased by a layer of 

 pieces of platinum foil (b) within the 

 crucible and in contact with its walls. 

 The joint between cap and crucible is 

 made water-tight by a thin rubber band 

 ■(F). The capacity of the cell is made 

 conveniently ample by attaching to the 

 crucible, by means of a close-fitting, 

 thin rubber hand (E), a glass chamber 

 (C) easily made from a wide, short test-tube. The second 

 electrode (f) is introduced from above through the glass 



*V. Klobukow, Jour, prakt. Chem. (N. F.), xxxiii, 473. Gooch and 

 Medway, this Journal, xv, 320. Exuer, Jour. Amer. Chem. Soc, xxv, 876. 



f Levoir, Zeitschr. Anal. Chem. xxviii, 63. Richards, Jonr. Amer. Chem. 

 Soc, xxvi, 530. 



\ Frary. Zeitschr. Elektrochum xiii, 308. Jour Amer. Chem. Soc, xxix, 

 1592. 



Am. Jour. Sci.— Fourth Series, Vol. XXV, No. 147.— March, 1908. 

 17 



