See Norman Stretton, 'The Indio Pottery at Bovey Tracey' E.E.C. Transactions, Vol. 8, pt.2, pls. 87 and 88 for other dated examples. It is tempting to connect this piece with one of the Ellis families at the Indeo Pottery. Brian Adams and Anthony Thomas show a family tree in A Potwork in Devonshire, p.17 that includes a Joan Prouse (sister of the foreman) who married Andrew Ellis (no relation to William Ellis II, the founder) in 1763. One wonders if Joan was given a dated tea cannister by her brother or husband and that the difference in the name was due to the inconsistancies in spelling at that time.