128 NOMOS. 



Attention having been thus called to the matter, it 

 was determined to inquire into the influence of heat 

 upon some of the principal stones in ordinary use 

 for building purposes, and with this view portions of 

 granite and marble and red sandstone were sub- 

 mitted to numerous and careful experiments. The 

 measurements were made by means of a white pine 

 rod with copper elbows at the tips, which elbows 

 were made to embrace the ends of the stone under 

 examination, and in every instance due allowance 

 was made for the expansion of the wood and metal ; 

 the expansion of the wood being at the rate of 

 0000306 of an inch in a foot for every degree of 

 Fahrenheit, and that of the metal -00011308 of an 

 inch in a foot for every degree of the same scale. 

 The particulars of these experiments are stated in 

 the paper, but it is enough for us to know that for 

 every degree of Fahrenheit a foot of granite expands 

 0000579 of an inch, a foot of marble -000068016 of 

 an inch, and a foot of red sandstone '000114384 of 

 an inch. These are the results of these experiments, 

 and these are the data upon which we may attempt 

 to form some conception of the degree to which the 

 earth may expand under the action of solar heat 

 to form some conception, we say, for these data are 

 too uncertain, and the problem is too complicated, to 

 allow us to do more than guess at what may be the 

 degree of expansion under these circumstances. 



In order to form some conception of the degree to 

 which the earth may be affected by solar heat, we 

 may assume the case of an imaginary earth of solid 

 granite, and ask what would happen if it expanded 



