If he desires to sell under specification, the manufacturer must comply with his contract with respect to specific gravity, and he cannot greatly exceed the specific gravity specified without substantial sacrifice in cost of manufacture. It is therefore economical to determine the specific gravity of the product as accurately as practicable (see p. 51) and also to adopt methods of manufacture that will control as closely as possible the specific gravity of the finished product. Beginning on page 33, methods are given for the determination of specific gravity under various conditions of manufacture and sale, and on page 50 is given the method for the determination of specific gravity of the cyclone juice or partly concentrated pulp which this laboratory has suggested as an aid to determining the volume to which the product should be evaporated to secure the desired specific gravity. This method has been used by a number of pulp manufacturers and found to be relatively convenient and practicable. It might be used to better advantage and to considerably greater profit if more help were employed—and some times more competent help—in determining specific gravity and controlling the point at which evaporation should stop. The importance and economy of accuracy in the determination of specific gravity is not fully appreciated by all, though some of the larger manufacturers are now giving much attention to that subject. This matter is discussed on page 50. There is included in the bulletin beginning on page =13= a detailed description of the Howard method for the microscopic examination of tomato products, and following that a detailed statement of the chemical and physical methods employed in this laboratory for their examination. Such methods are only of value to those trained in laboratory work. They are included here because the laboratory receives many requests for these methods from chemists employed by manufacturers of pulp. Men who are employed only for the tomato season find special need for such information. Our correspondence brings many inquiries regarding the percentage of solids in pulp of different specific gravities, and also regarding the relative values of pulp of different specific gravities. In Table 10 (p. 59) there is given in parallel columns the specific gravities of pulp of different degrees of concentration and corresponding percentage of solids, and it is a simple matter to calculate the volume which the same pulp would make if concentrated to any other specific gravity. This calculation is explained on page =54=—in discussing the point at which to stop evaporation to secure pulp of any desired specific gravity.