BUEEAU OF SOILS. 209 



POTASH. 



Through its representative on the Pacific Coast the bureau has 

 kept in close touch with the development now going on in the in- 

 dustry of extracting potash from giant kelps. During the winter 

 the various plants then building or in operation were visited and the 

 processes being used or proposed for the recovery of potash from these 

 sea plants studied so far as possible. In addition, laboratory ex- 

 periments along the line of kelp distillation have been conducted. 



In cooperation with the Bureau of Fisheries, plans have been made 

 for a trial of the possibility of transplanting kelp plants and spores to 

 the Atlantic coast and establishing them in suitable localities. If this 

 can be accomplished it will afford a source of potash in close proximity 

 to the large fertilizer markets. 



The possibility of recovering potash as a by-product of cement 

 mills and blast furnaces is being called actively to the attention of 

 manufacturers. All the cement mills in the country have been 

 communicated with and arrangements have been made to secure 

 samples from these plants. When analysis of a sample shows a 

 sufficient potash content now volatilized and lost to warrant expendi- 

 ture for apparatus to recover it, the company will be advised. At the 

 same time figures secured from plants already recovering by-product 

 potash will be furnished. In the same way, a beginning has been 

 made in securing samples from blast furnaces and it is proposed to 

 continue this work actively. 



In addition, the question of extracting the potash from wool 

 scourings has received consideration and efforts have been made to 

 get in touch with the companies in the country which are engaged 

 in cleaning raw wool on a large scale. It has been found that several 

 of these companies are either now extracting potash as a by-product 

 or preparing to do so. It is proposed to investigate the methods being 

 used and to urge the extension of the practice in the industry so 

 far as possible. 



A number of alunite determinations were made and the fact 

 brought out that the optimum temperatures in calcining alunite for 

 potash recovery fall within comparatively narrow limits, too high 

 a temperature resulting in the formation of insoluble silicates and 

 too low a temperature involving the necessity of using excessive 

 amounts of water in leaching. A bulletin discussing the various 

 methods proposed for treating alunite for potash and giving the results 

 of these experiments was prepared and is in process of publication. 



NITROGEN. 



The bureau's laboratory at Arlington has been equipped with 

 apparatus for testing the different methods proposed for fixing at- 

 mospheric nitrogen, and contracts have been let for much additional 

 equipment to extend this work. This extension of the work has 

 been delayed by the impossibility of securing immediate delivery of 

 machinery. 



In connection with the work on phosphates, an electrical furnace 

 has been in operation working on the problem of volatilizing phosphoric 

 acid and fixing nitrogen in one operation. Apparatus has also been 

 installed for experimenting with the Ostwald process of oxidizing 

 ammonia for the production of nitric acid. Both these projects are 



