H. D. Minnig — Aluminium and Beryllium. 485 



That there is danger of inclusion of beryllium chloride could 

 readily be seen when the quantity of that substance was 

 increased. Unless the progress of the precipitation was 

 watched and the addition of the precipitating mixture stopped 

 as soon as the separation of the crystalline aluminium chloride 

 seemed to be complete, beryllium chloride could also be seen 

 to separate out.* Its appearance is very unlike that of the 

 aiuminium chloride and can easily be distinguished. Even 

 when the addition of the precipitating mixture was stopped 

 before the formation of this salt became noticeable in the 

 beaker, it appeared as soon as the supernatant liquid had been 

 poured through the filter and an attempt was made to wash 

 the precipitate. Increase in the quantity of aluminium 

 chloride seems also to have a like effect because of the neces- 

 sity for an increased volume of the precipitating mixture. 



The comparative insolubility of beryllium chloride in ace- 

 tone acetyl chloride (4-1) limits this process, therefore, to sepa- 

 ration of quantities of the two elements present as the chlorides 

 which do not exceed the equivalent of 015 grm. of the oxides. 

 Of this amount beryllium oxide should not greatly exceed one- 

 third. 



The use of acetyl chloride as a substitute for hydrogen chlo- 

 ride simplifies very much the method of Havensf and therefore 

 the favorable criticism of ISToyes, Bray and Spear;}: ought to 

 apply to this method as well as to that of Havens. These inves- 

 tigators found the method of Havens to be very reliable even 

 when the amount of aluminium present was exceedingly 

 small. 



* Probably the same compound mentioned on page 24 of Parson's book, 

 "The Chemistry and Literature of Beryllium." That precipitate was obtained 

 by the use of ether saturated with hydrogen chloride. 



fThis Journal (4), iv, 111. 



\ A System of Qualitative Analysis for the Common Elements, III, 19. 



