Various, Notes and Queries, Number 182, April 23…
“ Never filter, unless there is a great deal of extraneous matter at the bottom. If glass baths are used, cemented together with sealing-wax, &c., I imagine they might be as objectionable as gutta percha. The number of inquiries for a diagram of my head-rest, &c., from all parts of the kingdom—Glasgow, Paisley, Manchester, Leicester, Leeds, Newcastle, Durham, &c. &c.—proves the very large number of photographic subscribers "N. & Q." possesses. I think, therefore, it cannot but prove useful to discuss in its pages the question of the advantage or disadvantage of gutta percha. ”
