136 Expansion and Contraction of Building Stones. 
Art. XIV.—Experiments on the Expansion and Contraction of 
Building Stones, by variations of temperature; communicated by 
Witiam H. C. Bartierz, Lieut. U.S. Engineers. 
Fort Adams, Newport Harbor, March 12, 1832. 
TO PROFESSOR SILLIMAN. 
Sir—In the progress of this work, we have had occasion to use 
considerable quantities of Coping Stones, taken from different locali- 
ties, with all of which it has been found impossible to obtain tight 
joints. ‘The walls, on which these stones were placed, have not un- 
dergone the slightest change; and, notwithstanding they were laid 
with the greatest possible care, and their joints were filled with the 
best cements that could be devised, yet, at the expiration of a few 
weeks, these joints were broken up by fissures which extended from 
the top to the bottom of the Coping. These fissures were supposed 
to have arisen from a change of dimensions in the Coping stones, 
in consequence of the ordinary variations of atmospheric tempera- 
ture; and, with the view to ascertain if the total amount of crack- 
ing could be attributed to this cause alone, a series of experiments 
was instituted by order of Col. Totten, and continued from August 
18th, 1830, to June 2nd, 1831. The circumstances connected with 
these-experiments, as well as their results, you will find subjoined. 
Col. Totten requests me to communicate them to you, supposing 
that you may find them of sufficient practical importance to deserve 
a place in your Journal. 
‘These experiments were made, nearly at the same time, upon 
granite, limestone, and sandstone, the kinds of stone used for the 
Coping ; and for this purpose a piece of each was selected in such 
a manner that the three pieces were of nearly equal lengths. ‘The 
granite has a fine grain, is of a compact texture, and was taken from 
a boulder at the head of Buzzard’s Bay: the limestone is white, 
has a fine grained crystalline structure, and accompanies primitive 
rocks ; it was taken from the quarries of the Sing-sing State Prison, 
New York: the sandstone is from the quarries in Chatham, Conn. 
and belongs to the old red sandstone formation, according to the Rev. 
Edward Hitchcock ;* ithas a granular structure rather coarse, and its 
¢ement is argillo-ferruginous. 
es He now refers all the sandstone of the Connecticut valley to the new; see the 
first article in the present No. 
