Description
Glass lantern slide of an illustration with the caption, "Fig. 14 - Section of wood showing position of the grain at base of a limb. P, pith of both stem and limb; 1-7, seven yearly layers of wood; a, b, knot or basal part of a limb which lived four years, then died and broke off near the stem, leaving the part to the left of a, b, a "sound" knot, the part to the right a "dead" knot, which would soon be entirely covered by the growing stem." Reproduced from “Timber: an elementary discussion of the characteristics and properties of wood” by Filibert Roth. Washington, D.C.: Dept. of Agriculture, Forestry Division, 1895. Bulletin (United States. Division of Forestry) no. 10. No label on slide. Used to illustrate the course "Materials of Engineering Construction" which was taught between 1893-1950 at the Wagner Free Institute of Science, Philadelphia, Pa.
Sponsorship
This Digital Object is provided in a collection that is included in POWER Library: Pennsylvania Photos and Documents, which is funded by the Office of Commonwealth Libraries of Pennsylvania/Pennsylvania Department of Education.
