PHYSICS — BARUS. 235 



The results show that the displacement of ions during exhaustion is the 

 most serious source of discrepancy. On the other hand, the effect of gamma 

 rays on the outside of the fog chamber and of conduction currents is almost 

 negligible for a well-installed apparatus. In connection with this discussion 

 Dr. Barus undertakes the electrometric measurement of the voltaic potential 

 differences between the two conductors of a condenser separated by an ion- 

 ized medium. 



A summary of the work during the last two years has been completed and 

 will appear as part 2 of Publication 96 of the Carnegie Institution of Wash- 

 ington. 



Burgess, Charles F., University of Wisconsin, Madison, Wisconsin. Grant 

 No. 560. Investigation upon properties of iron and its alloys, based upon 

 the use of electrolytic iron. (For previous reports see Year Books Nos. 

 4, 5, 6, and 7.) $2,500. 



Mr. James Aston has devoted his entire time to the investigation during 

 the past year and has been assisted by Messrs. G. A. Roush and J. M. Breck- 

 enridge. 523 pounds of single-refined and 300 pounds of double-refined elec- 

 trolytic iron have been produced. This has been used in the production of 

 test samples and in supplying material to other investigators. Besides a large 

 number of alloys prepared previously, 87 new alloys have been added to the 

 collection, including practically carbon-free alloys of iron with manganese, 

 arsenic, bismuth, antimony, nickel, silicon, aluminum, and zinc. 



The greatest amount of attention has been given to the testing of the 

 magnetic properties of alloys, and nearly 1,000 magnetic records have been 

 obtained. The electrical resistance and other physical properties have also 

 been investigated. Methods of magnetic measurements have been studied 

 and comparisons are being made with results obtained in industrial labora- 

 tories. 



A study of the corrodibility of about 100 alloys is still under way, with a 

 view to determining the influence of the metallographic structure of alloys on 

 the corrodibility and the comparative value of rapid methods of testing corro- 

 sion with corrosion produced by atmospheric conditions. 



The publications of results which have been made during the past year 

 include the following: 



Observations of alloys of electrolytic iron with arsenic and bismuth, by C. F. Burgess 



and James Aston. 

 Influence of arsenic and of tin upon the magnetic properties of iron, by C. F. Burgess- 



and James Aston. 

 The absorption by iron of carbon from carbon monoxide, by Charles F. Burgess and 



James Aston. A paper for the International Congress of Applied Chemistry. 

 Effect of temperature on the magnetic properties of electrolytic iron, by E. M. Terry. 



Preliminary report to American Physical Society, November, 1908; publication ia 



full in Physical Review in near future. 



