114 F. S. Havens — Separation of Aluminum, etc. 



regulated current a mixture of strong aqueous hydrochloric 

 add and common salt. A platinum dish hung in an inverted 

 bell-jar, provided with inlet and outlet tubes through which 

 the current of water for cooling is passed, makes the best con- 

 tainer for the solution to be saturated with the gas. It is 

 advantageous to arrange the filtration upon asbestos so that the 

 filtrate and washings may be caught directly in the crucible 

 (placed under the bell-jar of the filter pump) in which the 

 subsequent evaporation is to be effected. The heating of the 

 strong acid solution must be gradual and conducted with care 

 to prevent mechanical loss by a too violent evolution of the 

 gaseous acid. 



It only remains to thank Professor Gi-ooch for kind sugges- 

 tions and advice. 



