30. Shingles are made by sawing or splitting chestnut, hemlock, cedar, white pine, or cypress.

Chestnut shingles are likely to curl in dry weather, and when damp they swell and bulge; this continued movement gradually draws the nails and cracks the shingle.

Hemlock shingles are more serviceable than is generally supposed, and in dry localities last a long time; but in a moist atmosphere they rot quickly.

Red-cedar shingles last very well, and are on this account largely used. Because of the general straightness of the grain, red-cedar shingles are not roughened so much under the sun as other kinds, and, therefore, give a better weather surface.

White-pine shingles are commonly used, because, while offering most advantages under general requirements, they last longer than any but cypress or white-cedar, and do not curl and split so readily as the foregoing kinds. Their chief disadvantage is in the sawing, as the fiber roughens quite freely.

Cypress and white-cedar shingles are the least used, and, at the same time, the best that can be had. The wood saws fully as well as the red cedar, and will not curl or split, except under excessively severe conditions; as regards enduring qualities, these shingles are far superior to any other shingles known.