Chemistry and Physics. 143 



add little by little while still shaking 25°° of 96 per cent alcohol 

 and let stand 6-8 hours. Decant the liquid through a 9 cra 

 " barium sulphate " filter, wash the precipitate six times hj decan- 

 tation with neutral 96 per cent alcohol, remove the filter from the 

 funnel and place it in the flask containing the precipitate. Then, 

 usino- phenolphthalein, titrate with 0*1 N NaOH in alcohol to 

 alkaline reaction. The end red color should persist for 5 min. 

 Then dissolve the precipitate in 0*1 N aqueous NaOH and titrate 

 the excess with 0-liVHCl. The NaOH used to dissolve the 

 bitartrate represents the K 2 present, the factor being 0-00471. 

 The principle of the method is interesting but nothing is said as 

 to the reason for making alkaline with alcoholic sodium hydroxide 

 before the actual titration, nor is any statement made in regard to 

 the interference of salts of magnesium or other metals with the 

 process. — Chem. Abstracts, ix, 3188. h. l. w. 



3. Potash from Feldspar. — In view of the present scarcity of 

 potash in the United States a writer in " Chemical Engineer " has 

 discussed this possible source of the material. It is stated that 

 the cost in Germany of producing one " unit " of potash (20 lbs. of 

 K 2 0) in the form of commercial "muriate" is less than 15 cents, 

 and that it could be delivered in the United States at a profit at 

 the rate of 30 cents per unit. Therefore any process must yield 

 potash at a lower price than the one last mentioned in order to 

 survive future German competition. Feldspar deposits of vast 

 extent have been located having an average run-of-mine composi- 

 tion as follows: 



Potassium oxide, K 2 11 percent. 



Sodium oxide, Na 2 2 " 



Silica, Si0 2 70 " 



Alumina, Al 2 3 17 " 



Many processes have been proposed for the extraction of the 

 potash from feldspar, but they are generally very unpromising as 

 far as competition with the German supply is concerned. Some of 

 the prominent methods propose, after ignition with lime, to use 

 the residue for making Portland cement, but since the clay and 

 lime used for this industry usually cost less than 3 cents per 100 

 lbs., the values are discouragingly low. Such processes as pro- 

 pose to separate and save the alumina are confronted by com- 

 petition with natural bauxite. One of these proposed processes is 

 theoretically interesting. It consists in heating the feldspar with 

 potassium chloride to 1050° C. when aluminium chloride sublimes 

 off. The remaining potassium silicate is easily converted into 

 potassium carbonate and an iron-free silica. The aluminium 

 chloride may be converted into alumina and carbon oxychloride. 

 The latter, it is said, acts upon hot feldspar to produce potassium 

 chloride. 



The article under review finally discusses an operation starting 

 with phosphate rock, common salt, feldspar and carbon dioxide 

 from the combustion of coal, and producing phosphoric acid, 

 soda ash, potassium chloride and alumina. It appears, however, 



