388 



Holborn and Day — Expansion of Certain 



t . 



0' 

 250 

 375 

 500 



Table VI b. 

 Constantan Bar. 



2' (mm.) 

 Sept. 24. Sept. 25. 



1-916 

 2-159 



1-903 

 1-040 

 1-106 



Observed 

 



1-910 

 2-950 

 4-063 



's (mm.) 



Calculated. 







1-910 

 2-956 

 4-063 



7. Wrought Iron. 



The bar of wrought iron as well as the steel bar described 

 below were provided, before beginning the observations, with 

 small platinum plates carrying the scale divisions, in the same 

 way as the nickel bar above. One of the scale intervals at 

 one end of the iron bar increased in length some 0*03 mm in 

 consequence of the heating, nearly all of it occurring during 

 the first day. None of the other divisions showed any notice- 

 able change. The observations were not continued above 750° 

 in order to avoid the permanent changes in the nature of metal 

 such as occur in steel especially after long continued heating 

 to high temperatures, The magnetic metals are known to 



Table Vila. 

 Iron Bar. 



July 19 



July 21 



July 25 



22-0° 

 1841 MV 

 4069 

 6564 



22-7° 

 1816 MY 

 2927 

 4077 

 6572 



22-6° 

 1803 MV 

 4066 

 5248 

 6538 



M 

 (mm.) 



1-267 



1-872 

 1-823 



1-259 

 1-266 

 0-987 

 1-951 



1-334 

 2-348 

 0-963 



1-188 



M' 

 (mm.) 



0-227 

 0-030 

 0-170 



0-207 

 ■0-364 

 •0-038 

 0-039 



0-129 

 0-473 

 0-016 



0-188 



2 

 (mm.) 



1-494 

 1-842 

 1-993 



1-466 

 0-902 

 0-959 

 1-990 



1-463 

 1-875 

 0-979 

 1-000 



22-0° 

 1847 MV 

 4068 

 6551 



22-7° 

 1823 MV 

 2930 

 4077 

 6567 



22-6° 

 1807 MV 

 4065 

 5244 

 6569 



M 

 (mm.) 



■277 

 •857 



1-854 



1-294 

 1-247 

 0-966 

 2-004 



1-376 

 2-305 

 0-956 

 1-213 



M' 

 (mm.) 



0-211 

 0-024 

 0-129 



0-166 

 0*349 

 0-014 

 0-027 



0-093 

 0-453 

 0-036 

 0-211 



2 

 (mm.) 



1-48S 

 1-833 

 1-983 



1-460 

 0-898 

 0-952 

 1-977 



1-469 

 1-852 

 0-992 

 1-002 



