16 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



The corporation seeks to do for industrial arts what some other 

 institutions are now doing for the sciences generally, for medicine, 

 and for the improvement of social conditions. There has now been 

 established an annual fellowship " open to general competition for 

 the purpose of encouraging and assisting scientists in the prosecu- 

 tion of their investigations. To the successful competitor, the cor- 

 poration offers an honorarium of twenty-five hundred dollars and 

 the assistance of the corporation in securing the most favorable op- 

 portunity for prosecuting the particular object of study." 



The Col troll process in operation has been described in publica- 

 tions of the Smithsonian Institution. The precipitation processes 

 and their applications have been briefly described as follows: 



Electrical percipitation consists of the removal of suspended partieles froju 

 gases by the aid of electrical discharges. The precipitation process operates 

 by passing the gases carrying the suspended, finely divided particles between 

 two systems of electrodes, one of which is made to carry a negative electrical 

 charge while the other carries a positive charge. In ordinary practice the 

 negative electrodes are small in size, such as iron wires or chains, and the 

 positive electrodes are large, such as iron plates or pipes. The gases are di- 

 vided into several channels and passed through the space between the wires 

 and the plates or pipes, in the latter case each pipe having a wire placed 

 along its longitudinal axis. The electrodes are charged by being connected 

 with a source of high voltage electricity, consisting ordinarily of a high volt- 

 age transformer for increasing the electric potential up to the working voltage 

 which varies with the size and character of the installation from 20.000 to 

 100,000 volts ; a rectifier for changing alternating current into direct current, 

 and a switchboard provided with the necessary standard control equipment. 

 The suspended particles while passing between the electrodes become electri- 

 cally charged and are then driven to the plates or the inner surface of the pipes 

 by the forces of the electric field. A common example of the application of 

 the process is the precipitation of minute particles containing copper, silver, 

 gold, lead, zinc, and other valuable metals ordinarily carried away from smelt- 

 ing and refining furnaces which may by this process be recovered from such 

 gases without interfering with the operation of the plant. The recovered dust 

 or fume, in such cases, is often valuable and constitutes a large financial sav- 

 ing. In many other industrial operations where noxious gases, fumes, or dusts 

 are given off, the process has been successfully applied, some of the materials 

 precipitated being sulphuric, nitric, and hydrochloric acids ; arsenic, bleaching 

 powder, lead, zinc, and other poisonous materials. 



NATIONAL RESEARCH COUNCIL. 



As stated in my last report, the National Research Council was 

 organized by the National Academy of Sciences, the President of the 

 United States appointing the representatives of the Government and 

 authorizing the appointment of other members by the president of 

 the academy. There was thus brought together about 50 members 

 representing various branches of science, and they were subdivided 

 in several subcommittees. Joint committees were also formed in 



