Democratic Sentinel, Volume 5, Number 31, Rensselaer, Jasper County, 9 September 1881 — Birch Bark Rubber. [ARTICLE]

Birch Bark Rubber.

It is said that a dense black gum may be obtained from the outer layers of the birch tree bark by distillation, which possesses all the ordinary properties of gutta percha, and has the additional merit of resisting the deteriorating influence of air and the corrosive action of acids. This advantage makes it useful as an ingredient of India-rubber and gutta percha, which it renders far more durable. Whether these statements are true remains t<? be proved.— Scientific American,