Shola,

Chambers's Encyclopaedia, Volume 9: Bound to Swansea, p. 414

Shola, or SOLA, the white pith of the leguminous plant Eschynomene aspera, a native of India. With this substance, which is exceedingly light, the natives of India make a great variety of useful articles, especially hats, which being very light and cool are in great request. Helmets made of shola are much used by the British in India.

Source scan(s): p. 0427