12 Gooch — Precipitates for Solution and Reprecipitation. 



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I have used also in the manipulation of such precipitates a 

 regularly made cone of 60°, fitted with eyelets for handling ; 

 hut the simple folded cone is, on the whole, more convenient. 

 Precipitates collected upon asbestos in the 

 perforated crucible are frequently removable 

 without difficulty by allowing a suitable solvent 

 to percolate precipitate and felt ; but in case 

 the precipitate is pasty or compacted, solution 

 in this manner may be unpleasantly slow. In 

 such cases, it is convenient to remove the 

 greater part of the precipitate, collected and 

 washed in the usual manner, upon a disc of 

 platinum foil, perforated, fitted with a wire 

 handle, as shown in the figure and placed upon 

 the asbestos felt before the transfer of the preci- 

 pitate to the crucible. To make such a disc, 

 shown in figure 2, is the work of a few moments 

 only ; and by its use pasty precipitates, such as cuprous sulphocy- 

 anide or the sulphides of the metals, are easily handled for 

 solution. 



These simple devices so facilitate the manipulation of preci- 

 pitates in many processes of analysis that they have seemed to 

 be worthy of description. 



