The presence of copper and lead is detected by the formation of black precipitates upon saturating with sulphuretted hydrogen the solution of the ash in hydrochloric acid; zinc, chromium, etc., are precipitated from the filtered solution upon addition of ammonium hydroxide and ammonium sulphide. It is frequently more convenient to apply special tests for the particular metal thought to be present, either directly to the pigment or to the ash. In this way, arsenic can often be recognised by treating a portion of the colouring matter in a test-tube, when it will sublime and collect upon the cool part of the tube in minute crystals of arsenious acid. Or, an acidulated solution of the detached pigments may be boiled with a piece of polished copper-foil, upon which the arsenic will be deposited as a greyish film: this can be sublimed, and otherwise further examined. Copper is easily detected and estimated by placing the acid solution of the ash in a tared platinum dish, and reducing the copper by the electrolytic method. Chromium is recognised upon boiling the colouring matter with potassium carbonate solution: in its presence, potassium chromate is formed, which is submitted to the usual distinctive tests for chromium. The colour of Prussian blue is destroyed upon warming it with caustic alkalies: indigo, which remains unaffected by this treatment, forms a blue solution if heated with concentrated sulphuric acid. The presence of terra alba, barium sulphate, etc., is best detected by the examination of the ash. Chalk, or marble-dust, is recognised by its effervescence when treated with an acid, as well as by the presence of a notable proportion of lime in the ash. Many of the flavouring mixtures added to candy may be separated by treating the sample with chloroform or petroleum naphtha and evaporating the solution to dryness over a water-bath, when their identity is frequently revealed by their odour and other physical properties. Of 198 samples of the cheaper varieties of confectionery examined by Health officials in the United States, 115 were adulterated. Plumbic chromate is a very common addition; 41 out of 48 samples of yellow- and orange-coloured candy contained this poisonous pigment. BEER. The name beer is most commonly applied to a fermented infusion of malted barley, flavoured with hops. Its manufacture embraces two distinct operations, _viz._, malting and brewing. Briefly considered, the former process consists in first steeping barley (the seed of _Hordeum distichon_) in water and allowing it to germinate by arranging it in layers or heaps which are subsequently spread out and repeatedly turned over, the germination being thereby retarded; it is afterwards entirely checked by drying the grain (now known as _malt_) in cylinders or kilns.