234 REPORTS OF INVESTIGATIONS AND PROJECTS. 



Other papers which are in the printer's hands or ready for publication 

 include the following: 



Physical properties of iron-copper alloys. 



Observations on the alloys of iron and manganese. 



The physical characteristics of alloys of iron free from carbon. 



Tests on alloys of iron for permanent magnets. 



The electrical resistance of iron alloys. 



Magnetic and electrical tests on iron-copper alloys. 



Physical properties of iron and nickel alloys. 



Magnetic and conductivity tests on iron-nickel alloys. 



Howe, Henry M., Columbia University, New York, New York. Grant No. 

 561. Completion of work of determination of the iuHuence of ingot size 

 on the degree of enrichment of the segregate in steel ingots, and the 

 homogeneousness of the ingots outside the region of maximum enrich- 

 ment. (For previous reports see Year Books Nos. 6 and 7.) $500- 



The last two grants (December 8, 1908, $200, and March 17, 1909, $300) 

 were for completing the investigation and in particular applying the Bau- 

 mann method of silver-printing to the ingots already examined and others. 

 Both these things have been done. A comparison of the results obtained by 

 a large number of observers, myself included, of ingots of various sizes 

 shows clearly that the degree of enrichment increases with the size of the 

 ingot, especially when this exceeds a moderate size, say about 20 inches 

 square. The influence of other variables is so great that it was necessary to 

 eliminate them by taking the average of a very large number of cases before 

 it became possible to prove clearly the positive effect of ingot size. What is 

 even more valuable than this is the fact, brought out incidentally by the in- 

 vestigation, that with skill and care segregation can be restrained within 

 limits which are negligible for most purposes, even in ingots as much as 20 

 mches square, so that there is no real need of greatly restricting ingot-size 

 in order to prevent segregation. 



Eleven ingots have been examined by the Baumann silver-printing method. 

 The results indicated that, though the method is valuable for a preliminary 

 reconnaissance, to indicate approximately the position of the richest spots, 

 so that if it had been invented at the time I began this investigation it might 

 have saved much time and money, yet its indications are not so precise as to 

 make it applicable to a series of ingots which has already been investigated 

 so thoroughly as those have which I have been studying. 



Besides the publications already reported, a paper giving some of the re- 

 sults of this investigation has appeared in Bulletin 34 of the American Insti- 

 tute of Mining Engineers, p. 909, Oct., 1900. 



