When an accurate examination of a pigment is required, the only course is to conduct an exact chemical analysis, which can only be done by an expert chemist in a well-equipped laboratory. But often it is necessary in the course of trade to decide rapidly the nature of a pigment or to detect the adulteration of a dear pigment with a cheaper, and for this purpose it is important to have a method of examination which can be conducted without much apparatus, and which requires no great chemical knowledge. It is quite possible to test the majority of pigments in a simple manner. Few reagents are necessary. For an examination of the mineral pigments the following are generally sufficient: hydrochloric, nitric and sulphuric acids, caustic soda solution and ammonium sulphide. The examination of a pigment containing organic compounds is somewhat more difficult, especially when it is necessary to ascertain the nature of the colouring matter. In this case additional reagents are required—stannous chloride, alum solution, etc. Since the present work is intended to meet the requirements of the practical man, the behaviour of the different pigments towards ordinary reagents is given in tabular form, the pigments of the same colour being taken together. Since the colouring matters of organic origin, as they occur in the lakes, require a rather more detailed examination, the testing of pigments composed of inorganic materials only is first given, afterwards the properties of the organic colouring matters, so far as is necessary, will be added. =Mineral Pigments.=—If the substance to be examined is in the form of a dry powder, it may at once be tested with the reagents mentioned, but if it is a paint or water colour, the oil or gum must be first removed, otherwise it would not be possible to recognise with certainty the action of the reagents. From water colours, which are ground with gum Arabic or tragacanth solution, it is easy to separate the pigment from the binding medium. The colour is allowed to stand in a tall narrow beaker with a somewhat large quantity of water. After some time the lumps become soft, they are then repeatedly stirred up, the pigment allowed to deposit, and the water, which now contains the binding medium, poured off.