368 Mr A. J. Adie on the Expansion of Stone 



sorb after having been dried, nevertheless the experiments on 

 greenstone show the effect of moisture, and some of the marbles 

 certainly became less sensible to the change of temperature, after 

 they had been heated, and this was probably caused by their natu- 

 ral moisture being driven off. This diminution is distinctly shewn 

 by the following series of experiments on Sicilian marble : — 



1st, 0325392 \ ( Decimals of an inch for 



2d, 0267163 * '"„.,'? I 23 inches, the change 



> 0013143 ' 



3d, 0254020 [ ' ' ) of temperature being 



m, * .0240656 ) ° 013364 { 180° F. 



The rod gave off a considerable quantity of moisture. This 

 gradual diminution of the expansion was scarcely observable in 

 the sandstones and Aberdeen grey granite, which contained a 

 great deal of quartz ; and in the bricks, in the stalk of a Dutch 

 tobacco-pipe, and in a rod of Wedgewood's ware, no such change 

 took place, although all these substances had been wet in cutting 

 the holes, &c. before they could be put into the pyrometer. The 

 Peterhead granite, again, which contains much more felspar than 

 that from Aberdeen, and also the greenstone, were affected by 

 losing their moisture, but more especially the latter, as shewn 

 by the following series of experiments made in November. Un- 

 luckily the first observation, which always differs most from the 

 others, was lost. 



2d, 0198379^1 ff 0017485 ( Decimals of an inch, the 



3d, 0180894 > * '* 002037 \ ex P ansion of 23 inches 



Uh, 0178857' ( for 180° F. 



As greenstone absorbs moisture much more readily than the 

 marbles, I replaced the rod again in the pyrometer, after it had 

 hung in the room for more than three months, from the time of 

 performing the first experiments. The instrument was heated 

 to 207° F., and this temperature was kept up without change 

 during the four hours in which I watched the alterations of the 



