Second: hold the egg between a bright light and the eye. If it is fresh, it will show a rosy tint throughout, without dark spots, as the air chamber is small; if not fresh, it will look cloudy, with many dark spots present. =TEA AND COFFEE.=--These substances are extensively adulterated, but the adulterants are almost without exception harmless. =Tea.=--The commonest forms of adulteration of tea are as follows: (_a_) Exhausted tea leaves which have already been used are dried and added. Their presence may be detected by the weakness of the infusion, made from a given quantity of the suspected tea, compared with a similar infusion made from tea known to be pure. (_b_) Leaves from other plants are sometimes dried and added; these are easily shown if an infusion is made and when the leaves are thoroughly wet unrolling and comparing them. (_c_) Green teas may be "faced" or colored with Prussian blue, indigo, French chalk, or sulphate of lime; black teas may be similarly treated with plumbago or "Dutch pink." If teas so treated are shaken up in cold water the coloring matter will wash off. (_d_) Sand and iron filings are occasionally added for weight; observation, and the fact that they sink when tea is thrown in water, will show their presence. Iron filings may be readily found by using a magnet. (_e_) The presence of starch may be shown by washing the tea in cold water, straining it, and testing the solution in the following manner: dissolve one-half teaspoonful of potassium iodide in three ounces of water and add as much iodine as the solution will dissolve; a few drops of this solution added to the suspected sample will give a blue color if starch is present. =Coffee.=--Coffee should always be purchased in the bean, as ground coffee is much more frequently adulterated and the foreign substances are more difficult to detect. The adulterants commonly used are: chicory, peas, beans, peanuts, and pellets of roasted wheat flour, rye, corn, or barley. Fat globules are always present in pure coffee; their presence may be shown by the fact that imitation coffee sinks in water, while pure coffee floats. Chicory is the most frequently used adulterant; it is added for flavor and to produce a darker infusion, thus giving the impression of greater strength. It is perfectly harmless and as a drink is actually preferred by some people. Its detection is comparatively easy. Chicory grains are dark, gummy, soft, and bitter; coffee grains are hard and brittle; a small amount put in the mouth will demonstrate the difference. Chicory will often adhere to the wheels of a coffee grinder, clogging them on account of its gummy consistency. When a sample of adulterated coffee is thrown in water the pure coffee floats and leaves the water unstained; chicory sinks almost instantly, coloring the water, while peas and beans sink more slowly but also color the water.