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                 itilil
   FROM the importance of good walls as a primary
 demand in all buildings, it follows that the consider-
 ation of the quality of materials of which they are
composed, as well as the manner in which the con-
junction or adhesion of parts can be most thoroughly
effected, is a matter of no small consequence.
   SToNE.-Being a natural production, and not only
adapted to the requirements of building with but
little preparation, but from its nature conducive to
the permanency of artificial structures, stone, as an
element of wall building, is entitled to the first rank,
and therefore to early notice.  Without going into a
geological disquisition on the subject, we may speak
of the relative value of different kinds of stone; not
always with the certainty we could wish, from the
fact that time enough has not elapsed since an in-
terest has been awakened to the vast importance of
knowing the qualities of the stone employed.  Ex-
perience seems to be the best test; although the
science of chemistry may be sufficient for the geologist,
the architect is better satisfied with the proofs of
time.
  Granite, according to geology the primary rock,
exists in great abundance in this country, and has
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