According to this, we might group the cements as follows:
1. Cements for glass and porcelain, for repairing broken articles, for fastening glass letters upon show-windows, etc.
2. Cements for metals not exposed to an increase of temperature, for instance, for tightening the joints of gas and water pipes.
3. Cements for stoves and other articles, which have to stand an increased temperature.
4. Cements for chemical apparatus, i. e., such as will have to resist the action of chemical agents.
5. Cements to protect vessels of glass, porcelain, or metal against the action of fire.
6. Cements for filling hollow teeth, for microscopical preparations, and other delicate articles.
7. Cements for special purposes, for instance, for cementing meerschaum, tortoise shell, etc.
Chemical nature of cements. The different varieties of cement frequently contain substances which act chemically upon each other, or upon the bodies to be united with them. To determine the practical availability of a variety of cement for a determined purpose, it is of importance to know the reciprocal behavior of these substances towards each other, as from this we are able to judge at once whether a cement is suitable for a certain purpose or not.
Oil cements. The fluid fats, commonly called oils—though there are oils which remain solid at the ordinary temperature, as, for instance, palm oil and cocoanut oil—may, as regards their behavior on exposure to the air, be divided into two large groups, namely, drying and nondrying oils. As samples of these groups may be mentioned olive oil and linseed oil.