Green’s Dictionary of Slang

1. phosphorus, used by burglars for illumination; thus ding the phos v., to throw away the bottle of phosphorus.

1811		Lex. Balatronicum n.p.: Phos Bottle. A bottle of phosphorus: used by housebreakers to light their lanthorns. Ding the phos; throw away the bottle of phosphorus.
1812		Vaux Vocab. of the Flash Lang.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.

2. phosphorus necrosis.

1892

Star 18 Jan. 2/5: The manager denied she had ‘got the phos.’ and refused any money .