22 THE GRANITES OF MAIN I.. 
Hampshire, s'how that specimens of granite, in a gaged length of 
20 inches and a diameter of 5.5 inches at the middle when placed 
under a load of 5,000 pounds to the square inch, suffered compression 
ranging from 0.0108 to 0.0245 inch, resulting in a lateral expansion 
ranging from 0.005 to 0.00T inch, and giving ratios of lateral expan- 
sion to longitudinal compression ranging from 1 : 8 to 1 :-17." 
Flexibility.— Although granite contains a large amount of brittle 
material (estimated at from ?>{) to 60 per cent ) and the interlocking of 
its various particle- give to it great cohesion and rigidity, yet in sheets 
of sufficient thinness and area! extent it is flexible. Sheets half an inch 
thick and 4 feet long may be bent, as noted in the description of the 
Lawton quarry, at Norridgewock, page 151. 'Whether flexibility in 
this case was conditioned upon a slight loosening of the grains by 
chemical and physical change is uncertain. 
Hardness. — As will be seen by reference to the tests for hardness 
described on page 64, granites differ greatly in hardness. This dif- 
ference is due not merely to differences in the percentage of quartz, 
but also to variations in the character of the feldspars. 
Expansibility. — The expansibility of granite has been variously 
tested. Bartlett 6 found that a piece of granite coping 5 feet long, 
under the effect of a winter temperature of 0° F. and a summer tem- 
perature of 90° F., expanded 0.027792 inch, or 0.000004825 inch 
per inch for each degree. The Ordnance Departmenl at the Water- 
town Arsenal tested the granites referred to tinder the heading 
"Elasticity,' 1 and found that slab- of gaged length- of 20 inches in 
passing from a cold-water bath at 32° F. through a hot -water bath 
at 212° F., and back again to cold water at 32 F., expanded from 
0.0017 to 0.005!) inch, averaging 0.0040 inch. 
Porosity. — Granite contains and absorbs water, which is held in 
microscopic spaces both within and between its constituent minerals. 
Ansted d states that granite generally contain- about 0.8 per cent of 
water and is capable of absorbing about 0.2 per cent more. In other 
words, a cubic yard of granite weighing 2 tons contains in its ordi- 
nary state about 3| gallons of water and can absorb neatly a gallon 
more on being placed in pure water for a short period. Buckley ' 
found that the pore space or porosity in fourteen Wisconsin granites 
ranges from 0.17 to 0.392 per cent, and that the ratio of absorption 
(percentage of weight of absorbed water to the average dry weight 
of the sample) of the same granites ranges from 0.17 to 0.50. Mer- 
a Report of the tests of metals, etc., made with the United States testing machine at 
Watertown Arsenal, Mass. (1895), 18!><;. pp. :;:!i)-348. 
h Bartlett, Wm. C, Experiments on the expansion and contraction of building stones by 
variation of temperature: Am. Jour. Sci., 1st ser., vol. 22, 1832, pp. 136 1 in. 
c Op. cit., p. 322. 
"Ansted, I). T., quoted by Edward Hull in A treatise on building and ornamental stones 
of Great Britain and foreign countries, 1872, p. :;<). 
e Op. cit., p. 400. 
