Arsenic (To Detect). Arsenic is not freely soluble in any organic mixta and may generally be found as a white sediment, which, when thrown upon a red-hot cinder, gives out a Strong odour, like that of onions thick white smoke. The best test is the following: - Pour two table-ul of the suspected Quid into a six ounce bottle, and add seven table-spoonsful of water Then pour in one table-spoonful of sulphuric acid. Having prepared a cork with a piece of tobacco-pipe run through it, drop into the bottle a few scraps of zinc. 11y -drogen gas will be evolved, which, after waiting two or three minutes, may be lighted. If amnio is present the onion smell will be detected, and the flame will have a blueish-white colour. Upon holding a piece of glass, or a white saucer. over the point of the flame, black metallic in fine crystals, and white arsenic, will deposited. Common arsenic cannot bed by the taste.