Canada balsam definition of Canada balsam in the Free Online Encyclopedia.

Canada balsam, yellow, oily, resinous exudation obtained from the balsam fir balsam fir, common name for the evergreen tree Abies balsamea of NE North American boreal forests. It has small needles and cones and is used for lumber.
..... Click the link for more information. . It is an oleoresin (see resin resin, any of a class of amorphous solids or semisolids. Resins are found in nature and are chiefly of vegetable origin. They are typically light yellow to dark brown in color; tasteless; odorless or faintly aromatic; translucent or transparent; brittle, fracturing
..... Click the link for more information. ) with a pleasant odor but a biting taste. It is a turpentine turpentine, yellow to brown semifluid oleoresin exuded from the sapwood of pines, firs, and other conifers. It is made up of two principal components, an essential oil and a type of resin that is called rosin .
..... Click the link for more information. rather than a true balsam. On standing, the essential oil in Canada balsam evaporates, leaving behind the resin as a hard, transparent varnish. Canada balsam is valued as an optical mounting cement, e.g., for lenses and microscope slides, since it yields, when dissolved in an equal volume of xylene, a noncrystallizing cement with a refractive index nearly equal to that of ordinary glass. It is used also in paints and polishes.

Canada balsam [‚kan·ə·də ′bȯl·səm]

(materials)

A transparent balsam useful for cementing together lenses and other optical elements because its index of refraction is in the same range as that of glass.