TT PROPER SOB GLEDING SL ONES, 2 LG, 339 
The degree of polish which a stone will take and the con- 
trast of the hammered and polished surfaces can be best esti- 
mated from the finished work. One should be mindful, however, 
at all times, in making comparisons, not to allow the elaborateness 
or excellence of the workmanship to influence the judg- 
ment. Dealers sometimes oil the polished surfaces of the 
monuments, which gives a brilliancy and luster not inherent 
in the stone itself. For this reason a monument should 
only be examined after it has been erected for six months ora 
year. 
In the case of stone used for highways and sidewalks much 
can be learned of its strength and durability by inspecting 
previously constructed walks and roadways. In these cases, 
however, a just comparison can only be made when the manner 
in which the highway or walk has been constructed, the amount 
of traffic to which it has been subject, the character of the sub- 
soil, the climate conditions, and the data of construction are 
known. The rapidity and manner in which a stone pavement 
wears are the important factors to be determined. An examina- 
tion of pavements built out of the stone will indicate whether it 
wears unevenly, is slippery, or is easily abraded. 
LABORATORY TESTS 
One who is fully acquainted with the mineralogical and 
chemical composition, the physical characteristics of a stone, 
and the climatic and other conditions to which it will be subject 
when in use, can predict with a remarkable degree of accuracy, 
without inspecting the quarry or examining buildings of long 
standing, the results of exposure to the atmosphere. It is not 
always possible to have a laboratory examination made, and fre- 
quently it is unsought for by quarrymen, who often prefer to 
rely upon their own statements to sell their stone. 
The important laboratory tests are included under three 
general classes, viz., (1) chemical; (2) microscopical; and (3) 
physical. 
