in the presence of Calcium and Magnesium. 523 



was then added, and a stream of hydrochloric acid gas was 

 passed for two hours into the cooled mixture. The precipitates 

 were then treated as in the former experiments. The results 

 show that even in the strongest possible solution, at the ordi- 

 nary temperature, of hydrochloric acid barium chloride is 

 soluble to a considerable degree, this solubility amounting 

 according to the first three experiments of the series to about 

 one part in 20,000. In Exp. 18 and 19 ten cubic centimeters 

 of absolute ether were added to the solution before passing in 

 the hydrochloric acid gas. The results showed that the ether 

 seemed to decrease the solubility of the barium salt, and there- 

 fore the experiments of the following series were undertaken. 











Series E. 









Exp. 



BaCls . 2H 2 0. 



HC1. 



Ether. 



BaCl 2 . 





Loss. 



21. 



0-5008 



grm. 



50 cm 



3 10 cm 3 



0-4267 grm. 



0-0002 grm 



22. 



0-5002 



u 



50 " 



10 " 



0-425? 



a 



0-0007 " 



23. 



0-4999 



u 



50 " 



10 " 



0-4252 



a 



0-0009 " 



24. 



0-4999 



a 



50 " 



10 " 



0-4258 



cc 



0-0003 " 



25. 



0-5003 



a 



25 " 



25 " 



0-4259 



a 



0-0005 " 



26. 



0-5002 



cc 



25 « 



5 " 



0-4262 



cc 



0-0002 " 



27. 



0-5099 



a 



25 " 



5 " 



0-4344 



u 



0-0003 " 



28. 



0-5003 



u 



25 " 



5 " 



0-4261 



cc 



0-0003 " 



The experiments of Series E were conducted as follows. 

 The amount of barium salt specified was dissolved in the least, 

 convenient, amount of hot water (about 2 cm 3 ) and precipita- 

 tion was brought about by adding the indicated amount of 

 concentrated hydrochloric acid. The beaker containing the 

 precipitate was then placed in cold water and the amount of 

 ether shown in the tables was added and mixed with the solu- 

 tion by thorough stirring. After standing for five or ten 

 minutes the precipitate was filtered off and washed with con- 

 centrated hydrochloric acid containing about ten percentum by 

 volume of absolute ether and dried, sometimes in an air bath 

 at 165°-175° C. and at others over a radiator giving a tempera- 

 ture of 175°-200° C. A constant weight was more quickly 

 obtained by the latter method and it was used exclusively in 

 the experiments of the subsequent series. In using it a low 

 heat was used at first and the temperature was not increased 

 until the precipitate was moderately dry. The results show 

 that barium chloride is practically insoluble in a mixture of 

 hydrochloric acid and ether containing about one-sixth by 

 volume of the latter. The average solubility calculated from 

 the experiments given is one part in 122,000. The actual 

 solubility is less than this since no account was taken of the 

 volume of the washings which were at least equal to the orig- 

 inal filtrates. 



