Chloride of Alumininm and its Analysis. 243 



composed. There Mas no visible particle of residue, and the solu- 

 tion was perfectly transparent and colorless. Tl;e tube was removed 

 and repeatedly washed with pure water, and the washings added to 

 the solution of the cliloride. 



The tube when dry and wiped as before, together with the filings 

 of glass weighed 4.381 grammes. The chloride of aluminium in 

 the tube weighed 5.027 - 4.381 = 0.640 grammes. 



B. Nitrate of silver was added to tlie solution (A) in slight excess, 

 the precipitated cliloride of silver being repeatedly stirred well around 

 with a glass rod to prevent any of tlie solution from being mechani- 

 cally enclosed by it, and from thus remaining unacted on. When 

 the supernatant liquid became perfectly limpid, it was carefully drawn 

 off with a glass syringe. Tlie precipitate was repeatedly washed 

 with pure water, and the clear liquid drawn off in the same manner. 

 The chloride of silver was thrown upon a double filter of equal 

 weights, care being taken to wash every visible particle of the chlo- 

 ride from the precipitating glass into the filter. The washing was 

 then continued until there was no trace of cloudiness in the washings 

 on adding a drop of muriatic acid, (a small excess of nitrate of sil- 

 ver having been employed in precipitating the chloride.) The edges 

 of the filter were kept continually wet with a dropping bottle, and 

 to prevent any evaporation on the filter and consequent deposition of 

 matter in solution, the funnel in which the filter uas contained was 

 kept covered with a glass plate, except when the dropping bottle was 

 in requisition to wash down the edges of the filter. After the wash- 

 ing was finished, the funnel containing the filter, was placed in a stand 

 on the sandbath, and covered loosely with paper to prevent the ac- 

 cess of dust and to allow the evaporation to go on with little obstruc- 

 tion. The filter when nearly dry was removed from the funnel, pla- 

 ced on a capsule on the sandbath, and still covered with paper. In 

 this the evaporation was more uniform than in the funnel. In a few 

 days the drying was as complete as the temperature of the sandbath 

 could make it.* The filters were separated and placed in the oppo- 

 posite scales of the balance. The filters being of equal weight, the 

 difference in weight between the loaded and unloaded filter, would 

 give the weight of chloride of silver. This difference of weight 

 was 2.056 grammes. 



2.002 grammes of this chloride were fused on a piece of thin green 

 glass weighing 2.996 or both weighed 4.998 grammes. After fu- 



♦ The temperature ranged from 100° to 220° F. 



