THE PROPERTIES OF BUILDING STONES, ETC. Sod 
received, one should be personally acquainted with the possibili- 
ties of the quarry. 
OBSERVATIONS ON BUILDINGS 
The inspection of constructions of long standing is generally 
recognized as an important means of estimating the strength and 
durability of stone. The value of such observations, however, 
is often overestimated and it frequently happens that strong and 
durable stone is condemned on account of careless methods of 
handling and laying. 
An estimate of the strength and durability of a stone from its 
condition in a building should only be made after one has con- 
sidered, (1) the age of the building; (a) ts sivee (g)) wae 
climatic or atmospheric conditions; (4) its position ; (Ss) Wane 
grade of stone used, and (6) the manner in which the stone 
was quarried, handled, dressed, and laid. 
The age of a building is especially important, it being worse 
than folly to pass judgment on the stone in a building, unless 
this is known. A stone may not exhibit any material deteriora- 
tion during the first twenty-five years in a wall, although the 
next ten years may show marked decay. As a rule the actual 
disintegration of the stone in buildings in the United States is 
comparatively little. Many that are fifty or more years old do 
not exhibit the first signs of decay. The actual disintegration 
is frequently so little that the observer must content himself 
with searching for the beginnings of decay. 
The height of a building usually increases the weight of ‘the 
superstructure and hastens the rate of decay. The atmospheric 
or climatic conditions, temperate, torrid, frigid, InehaainGl,  Ofr 
arid, will affect the permanence of a rock. A stone which 
would remain unchanged for centuries in an arid region might 
crumble and decay in a few years in a moist, temperate 
climate. 
The position of a building, in the business or residence part 
of a city, protected or exposed to the storms and prevailing 
winds, will affect more or less the life of the stone. 
