Waterwheel at Combe House Hotel in Holford, Somerset, England. The overshot waterwheel was cast by Bridgwater ironfounder H Culverwell & Co in 1892 to replace an earlier wheel. It was used to grind oak bark for the tannery complex established here in the 1840s by James Hayman. When the tannery closed in 1900 the waterwheel was adapted to other uses such as grinding grain for grist, cutting chaff, chopping apples for the cider press and generating electricity. It also cracked stones in a nearby quarry. The gearing survives too.
In Europe, oak is a common source of tanbark. Quercitannic acid is the chief constituent found in oak barks. The bark is taken from young branches and twigs in oak coppices and can be up to 4 mm thick; it is grayish-brown on the outside and brownish-red on the inner surface.
^Flavan and procyanidin glycosides from the bark of blackjack oak. Young-soo Bae, Johann F.W. Burger, Jan P. Steynberg, Daneel Ferreira and Richard W. Hemingway, Phytochemistry, Volume 35, Issue 2, January 1994, Pages 473-478, doi:10.1016/S0031-9422(00)94785-X