Gypsum is tested for fineness in the usual way by rubbing up with turpentine in comparison with an approved sample and may be wet up with water in order to see that no error has been made as it has happened that partly calcined gypsum was shipped. A sample of the material should be dried at 212 degrees Fahrenheit, so that any excess of moisture be driven off without disturbing the water of crystalization. It has been the experience of the writer that, when gypsum had been allowed to remain too long on steam drying pans, although they were heated with exhaust steam only and the temperature hardly ever showing up higher than 150 degrees Fehrenheit, the material had lost several per cent of its combined water; at least, it was so found by the chemical laboratory test, that had two weeks previously found the goods normal in receipt. Gypsum has an average specific gravity of 2.33 and weighs 7 pounds per gallon packed dry, though some shipments that have absorbed moisture in transit will be found to weigh as much as 8 pounds. When gypsum has been well freed from moisture by drying, 80 pounds of pigment and 20 pounds of linseed oil will produce a medium stiff paste, weighing about 15 pounds per gallon, while 14 pounds pigment and 26 pounds of oil will make a semi-paste, weighing about 13 pounds per gallon and 63 pounds pigment and 37 pounds of oil would be a liquid transparent paint, weighing about 11 1/2 pounds per gallon. Gypsum and china clay with or without the addition have been used some years ago as the pigment for paste wood filler, but we have good reasons to believe that at least the use of gypsum in this connection has been pretty generally abandoned.