384 



HoTborn and Day — Expansion of Certain 



Jan. 19. 



Table III 6. 

 2' (mm.) 

 Jan. 24. 



Jan. 26. 



250 

 500 

 750 



1000 



1-033 

 1-111 

 1-204 

 1-308 



1-034 



1-110 



1-213 



\ 1-294 



1 1-287 



X 

 Observed 







1-033 



2-150 



3-357 



4-645 



s (mm.) 



Calculated. 







1-033 

 2-151 

 3'355 

 4*645 



1-031 

 1-130 

 1-202 



1-277 

 1-280 

 1-280 



in the first oven tube. Being the first observations made, the 

 above described scheme was not exactly followed. For the 

 temperatures below 1000° only a single set of measurements 

 was made upon this bar; it had received a preliminary heating 

 like the others however. The length at 0° was 483-l mm and 

 the formulae are 



X s = 3-960^ + 0-0006 85 tf(ix) 



X = { 8198* + 1-418^ }10- 9 



4. Silver. 



The silver bar was 6 mm in thickness and carried seven divi- 

 sions at each end, notwithstanding which the expansion was so 

 great that not all the divisions were visible at all temperatures. 



The preliminary heating was carried up to 900° and the per- 

 manent increase in the length which resulted amounted to 

 0'13 mm . The silver became very soft at this temperature and 

 could with difficulty be prevented from sagging slightly. 

 Partly for this reason probably, and partly because the perma- 

 nent changes in the length after heating were larger than with 

 any of the other bars, the observations at the higher tempera- 

 tures disagree somewhat more widely among themselves. The 

 last observation at 875° is not included in the calculation. The 



Table IV a. 

 Silver Bar. 



June 22 



June 23 



20-2° 

 1787 MV 

 4088 

 6548 



20-2° 

 1792 MV 

 4116 

 6516 



7937 



M 

 (mm.) 



1-216 

 2-254 



2*802 



0-149 

 1-905 

 1-340 

 1-049 



" M' 

 (mm.) 



0-945 

 0-386 

 0-096 



2-325 

 0-771 

 1-487 

 0-603 



(mm.) 



2-161 

 2-640 



2-898 



2-176 

 2-676 

 2-827 

 1-652 



20-2° 

 1797MV 



4103 

 6548 



20-2° 

 1804 MV 

 4132 

 6581 

 7949 



M 

 (mm.) 



1-252 

 2-237 

 2-815 



0-111 

 1-873 

 1-394 

 1-014 



M' 



(mm.) 



0-929 

 0-407 

 0-073 



2-304 

 0-785 

 1-456 

 0-637 



2 

 (mm.) 



2-181 

 2-644 



2-888 



2-193 

 2-658 



2-850 

 1-651 



