Properties, Specific Resistance, and Hardness of Steel. 357 

 Table V. 



No. . 



Resistance. 



S. 



AS, 



AS 

 T. E. H.' 



D...... 



C 



B 



A 



00209 

 0-005J2 

 0-00595 

 0-00908 



0-1654 

 0-2065 

 0-2271 

 0-3804 



0-0293 

 0-0704 

 0-0910 

 0-2443 



2320 

 2860 

 2150 

 2090 



The experiments now following, under the heads C and D, 

 have more a descriptive character than one of precise measure- 

 ment; the results are therefore given with one decimal less. 

 For the determination of T. E. H. the rods coming under 

 these heads were compared indirectly with the rod VIII. 

 (Table II.), for the T. E. H. of which the number 0-000069 

 (as above found) was assumed. 



C. The T. E. H. and AS for glass-hard rods; diameter = 2-30 

 millims. These were hardened by the aid of a blast-lamp. 

 The flame of the latter was for this purpose directed horizon- 

 tally and placed directly over a trough containing cold water. 

 In this way the rod could be transferred with great rapidity 

 out of the flame into the water. 









Table VI. 





No. 



T. E. H. 



Resist- 

 ance. 



s. 



AS, 



AS 

 T.E. H." 



Remarks. 



*[II] 



*[ILT] 

 *[IV] 



*[V] 



*[vT 



*[LTIJ' 



0-000138 



131 

 130 

 130 



116 



136 

 133 



0-0121 



0-0129 



107 



123 



0-421 



0-442 

 0-366 



0-430 



0-285 



0-306 

 0-230 



0-294 



2100 | 



2300 

 2000 1 



2200 1 



7l 



Heated yellow and sud- 

 denly cooled. 



t> W )> 



)J )) >> 

 )> >) » 



Heated red and suddenly 

 cooled. 



Obtained by reheating 

 [III] and [IV] to yel- 

 lowness and suddenly 

 cooling. 



D. The T.E.H. and AS of rods 0*678 in diameter, har- 

 dened f in the apparatus § II., afterwards annealed by immer- 

 sion in hot linseed-oil. 



t The T. E. H. of these rods in the glass-hard condition varied from 

 50 : 10" to 60 : 10 5 . 



Phil. Mag. S. 5. Vol. 8. No. 50. Nov. 1879. 



2B 



