Green’s Dictionary of Slang

a large, many-layered black cravat, used to show off one’s stick-pin and similar jewellery; such an item was especially favoured by 19C commercial travellers.

1860		Hotten Dict. of Modern Sl. etc. (2nd edn) 112: Cataract a black satin scarf arranged for the display of jewellery, much in vogue among ‘commercial gents.’.
1864, 1867, 1870		Hotten Sl. Dict.
1909		(ref. to 1840s) in J. Ware Passing Eng. of the Victorian Era.