138 Expansion and Contraction of Building Stone. 
sixty degrees Fabr. But to abridge the calculation, the difference 
in length between the stone and measuring rod, as shown by the 
wedge W, was subtracted from the length of the rod before making 
the reduction for the temperature of the latter. The length of the 
copper part, and that of the wooden part, were calculated separate- 
ly on account of their different expansibilities. The result of this 
calculation is the following table. 
MARBLE. : GRANITE. SANDSTONE. 
No. of | Degrees} Length in | Degrees} Length in | Degrees} Length in 
Experi. | Fahr. Inches. Fahr. Inches. Fahr. Inches. 
6° | 93.4155 6° | 94.025] 6° | 94.0180 
4 93.4277 8 | 94.0330 8 94.0153 
9 | 93.4201 9 | 94.0260 9 94.0052 
10 | 93.4207 10 | 94.0265 10 94.0088 
; 94.0230 11 94.0124 
12 93.4186 12 94.0282 13 94.0211 
14 93.4174 14 | 94.0271 14 94.0206 
14 | 93.4294 14 94.0347 14 94.0220 
14 | 93.4308 14 | 94.0361 15 94.0235 
10 16 | 93.4302 16 | 94.0285 15 94.0238 
11 16 | 93.4291 16 94.0345 17 94.0214 
12 17 93.4305 17 | 94.0358 18 94.0181 
13 19 93.4327 19 94.0416 | 20 94,0239 
14 20 93.4310 | 20 | 94.0364 | 22 94.0258 
15 21 93.4316 | 21 94.0440 | 22 94.0263 
16 31> | 93.4265 32 94.0324 32 94.0371 
17 32. | 93.4352 32 94.0406 34 94.0466 
18 34 | 93,4422 36 | 94.0330 38 94.0554 
i 36 93.4360 | 36 | 94.0450 39 94.0436 
20 36 93.4357 37 94.0483 39 94.0592 
21 38 | 93.4436 41 94.0344 | 43 94.0486 
22 52 | 93.4323 52 94.0348 53 | 94.0560 
23 58 93.4450 62 94.0541 64 94.0718 
24 83 | 93.4655 86 94.0720 93 | 94.0879 
25 86 93.4649 88 94.0737 93 | 94.0829 
26 90 | 93.4709 88 94.0688 95 94.0897 
27 99 93.4677 89 94.0731 99 94.0941 
OMDWIANh ON 
_ 
— 
© 
oo 
nN 
_ 
(9) 
— 
— 
_ 
28 . 90 | 94.0693 | 100 94.0906 
29 : Soon 91 94.0693 | 101 94.0944 
30 : vee. 94 94.0628 | 104 94.0841 
31 ee 102 94.0721 | 109 94.0792 
he is probable that many of the discrepancies here noticed were 
Owing to the hygrometric state of the stone ; and perhaps, in part, 
to imperfections in the measuring apparatus; but as the hygrome- 
