182 SIGIDMES, SHOU SIMGIQIEIN TSS 
Much care should be exercised in quarrying stone in order to 
prevent these unnecessary injuries. So far as practicable, quar- 
rymen should take advantage of the natural joints. Whenever 
blasting becomes necessary, the Knox system of small charges, 
properly distributed, is reported to be the least injurious of any 
method yet employed. The channeling machine, however, is 
the best method of reducing the stone to dimensions that can be 
easily handled. Especially in working sandstone and limestone 
this machine can be employed to advantage. 
The time of cutting and dressing stone may also influence 
in a small way its life It is generally known that during the 
process of seasoning the water which comes from within the rock 
evaporates and deposits mineral matter which forms a crust on 
the surface of the stone. This crust may be formed entirely by 
‘tthe evaporation of the original interstitial water, or it may be 
added to by water which has been soaked into the stone at a 
later period and been subsequently brought to the surface.* 
That water, which has been called the water of imbibition, proba- 
bly carries a much larger percentage of mineral matter in solution 
than the water of saturation. The water of imbibition is the last 
of the quarry water to leave the stone, and therefore the crust is 
not likely to be well formed until the rock has been thoroughly 
seasoned. If the stone is to be seasoned before being placed 
in the wall, it is advantageous to have it first cut, dressed, and 
carved. Not only is it advantageous to observe this rule from 
the standpoint of future durability, but also from the fact that 
the stone often works much more readily when first quarried 
thane ivudoes) alter jit has) beeni Seasoned ay Antena yenustmnias 
once formed it should not be broken, because the softer rock 
underneath, when exposed at the surface, will disintegrate much 
more rapidly. For these reasons most stone should be worked 
and finished, ready for laying in the wall, before it has been 
thoroughly seasoned. 
«The addition through saturation and evaporation after the quarry water has 
been driven off is probably an almost unappreciable amount, depending upon the 
amount of mineral matter originally in the water. 
