216 
STATE AGRICULTURAL SOCIETY. 
on exposure the stone, in its best condition is weak, offering little 
more resistance to a crushing force than common brick. These 
buildings cannot with all possible care be long preserved by 
the means at present adopted. But if the stone could be 
rendered permanently and absolutely impermeable to moisture 
the principal difficulty would be removed; and this may perhaps 
be done by some means known to the arts, or wdiich may be 
discovered by experiment. For this purpose I would recom¬ 
mend that specimens of the stone be carefully analyzed, and 
that a series of experiments be tried, with a view of finding 
some chemical agent, the application of which will prevent its 
absorption of moisture and thus strengthen and render it 
durable." 
These are notable illustrations of the prevailing carelessness 
and ignorance in the selection of building stone. It is sur¬ 
prising that in the erection of these magnificent edifices upon 
which millions of the people’s money has been expended, so 
little pains should have been taken that they have begun to 
decay, even before they are finished. In selecting stone for 
building structures which are to be exposed to the influence of 
weathering, there are several important points to be observed. 
1st. Observe Iioav the stone weathers in its natural exposure. 
If it forms bold angular cliffs, a smooth even surface, not 
pitted, cavernous or furrowed by irregular disintegration; if 
its fallen masses have sharp corners, and a solid appearance 
instead of being split by the frost into small fragments, you 
may rely upon its durability. 
2d. Where stones are found beneath the surface or are only 
seen above it in rounded knobs, fragmentary and decaying, 
great caution should be used in employing them. They 
must be regarded as worthless till the contrary is shown by 
experiment. 
3d. The principal causes of tfye decay of stone in our climate, 
are, the absorption and freezing of water, and expansion or 
contraction of stone consequent upon it. Stones should there¬ 
fore be carefully examined with reference to this quality. Dr. 
Ure mentions a test of durability which has been successfully 
