20 ROYAL SOCIETY OF CANADA 
necessary heating of the calipers, and the mean of several readings was 
taken as the final result. Though Reade neglected to state for just what 
range of temperature his determination was made, the range, as in most 
of the earlier experiments, was probably not very great, as the specimens 
of rock were placed on wood. The coefficients of expansion according 
to Reade are per degree Fahrenheit, and are as follows: 
FOS SL OMERE NAME heed cod Us et hide ace ee 7s a5 
a lac en ee ere fa ie OO elt docile ol ihe OU NT 
NES 1 PARENT AL 7 eet ease hes Pet hs nhs Lv EU leet ET 
CAM acct sO rear ie CURE CN die eae HET 
“Mean of the whole 
Fahr.” 
sus — 2.77 feet per mile for every 100° 
Reade gives results obtained by A. J. Adie ! as follows: 
“The mean coefficient of the thirteen determinations of the ex- 
pansion of stone is 55755 ; but if we omit the last coefficient, viz; that 
of the Black Marble from Galway, (which is probably an error, being 
so much less than those of the other marbles, and also of my own deter- 
mination of the expansion of Irish Black Marble), the mean coefficient 
will be HS : showing a remarkable agreement with my own results. 
“In Mr. Adie’s experiments he used longer bars of stone, namely, 
23 inches long and from 4 to 1 inch square, and heated them with a 
steam jacket, using much more complicated apparatus than mine.” 
Reade also refers to the experiments conducted by W. H. C. Bartlett 
by order of Col. Totten’, in 1832, the object of which was to ascertain 
the cause of the fissuring of the joints of coping-stones at Fort Adams, 
Newport Harbor, the conclusion reached being that the fractures were 
due to ordinary changes of temperature. 
“These experiments were made with three bars of the several 
stones mentioned, measuring 94 inches long (nearly). The measuring 
instrument was a pine rod with copper elbows, fitted with a graduated 
wedge for measuring. The variations of temperature ranging through 
100° were those due to the atmosphere, which affected both the measur- 
ing rod and the stone, the actual expansion being calculated from the 
differences of expansion.” The results are given as follows: 
HCranites.4 lat kd Stee a 000004825 = 35 553 
Marble ess 5.02 atk So etes 000005668 — 530 
BAUUSTONE. 1,4 WR ae 000009532 — RE 
DURA oly NN MES 165505 
! Trans. Royal Soc. Edin. Vol. XIII., p. 366. 
? Amer. Journ. of Science, Ist series, Vol. XXII, p. 136. 
