26 IOWA ACADEMY OP SCIENCE 



We next examined three specimens of salt, each of which was 

 supposed to be chemically pure. The following results in potas- 

 sium chloride were obtained : 



1. 0.57 per cent potassium chloride. 



2. 0.45 per cent potassium chloride. 



3. 0.49 per cent potassium chloride. 



In each of the seven samples of salt examined, the presence of 

 the potassium could be distinctly seen with the flame test, using 

 a piece of blue glass. 



The method we employed in separating the sodium and potas- 

 sium chlorides is the following : We dissolved about a half gram 

 of the salt in a little water and added perhaps twenty drops of a 

 ten per cent solution of platinic chloride. Then we added a few 

 drops of water and moved the mass back and forth till it flowed 

 freely. There is some difficulty of manipulation here, as too little 

 water would not dissolve all the Na, Pt Cl 6 , and too much would 

 dissolve some K 2 Pt Cl 6 . We filtered and washed first, five or six 

 times with one volume of water and a half volume of alcohol, then 

 about six times with a mixture of alcohol and ether. After dry- 

 ing the precipitate, it was placed over a weighed platinum cruci- 

 ble and washed into the crucible with boiling water. It was 

 evaporated to dryness on the water and dried in a thermostat at 

 105 degrees. 



Our thanks are due Clifford Lahman and Lester Rusk for as- 

 sistance in the analytical work. 



BARIUM IN TOBACCO AND OTHER PLANTS. 



NICHOLAS KNIGHT. 



Scheele in 1788 first observed that barium is found in plants, 

 as he obtained it from beech trees. Forchammer in 1855, detected 

 its presence in the ashes of beech, oak and birch trees. In the 

 same year, Eckhard and Boedeker confirmed its existence in beech 

 and found it also in the sandstone near*Goettingen. 



In 1874, Knap of Leipzig, while investigating the mud carried 

 down by the Nile river found that barium was present. The fol- 

 lowing year, Dwarzak confirmed the presence of barium in the 

 Nile mud, and found it in the leaves, ear and stalk of wheat 

 grown in the Nile valley. 



