1 8 John White 



Those most frequently obtained are 

 shown in the accompanying figure. In 

 some instances well defined interpenetra- 

 tion twins were obtained, the individuals 

 being arranged in the form of a Latin 

 cross. ^^^- ^ 



The washing of the crystals is most readily accomplished 

 by decantation, after shaking or mixing with absolute alcohol 

 (96 to 98 per cent), containing a trace of lead acetate, the final 

 washing being carried out on a Witt filter by the aid of the 

 pump ; the crystals were afterwards dried in a vacuum over 

 sulfuric acid. It, like the other salts previously described, is 

 stable only in dry air. The analyses were made in the same 

 manner as with the ammonium compound. The following re- 

 •suits have been obtained : 



A. 0.1447 gram substance gave 0.1201 gram lead sulfate. 

 0.1279 gram substance gave 0.1055 gram lead sulfate. 

 0.2620 gram substance gave 0.0792 gram silver iodid. 



After a further washing, the same substance gave: 



0.3134 gram substance gave 0.0960 gram lead sulfate. 

 0.1523 gram substance gave 0.1263 gram silver iodid. 



B. 0.1096 gram substance gave 0.0907 gram lead sulfate. 

 0.1074 gram substance gave 0.0333 gram silver iodid. 

 0.7587^ gram substance gave 0.2866 gram CO 2 and 0.1024 



gram H^O. 

 0.3256^ gram substance gave 0.1259 gram CO 2 and 0.0424 

 gram H^O. 



The formula deduced from these results is • , j.i_i_; , ; 



1 These analyses were kindly made for me by Miss Fossler. 



324 



