With the first method the amount of tomato juice pumped into the kettle, or the number of bushels of tomatoes from which this juice was derived, must be measured. This is a nuisance, and is not necessary with any of the other methods except the second. Furthermore, even though every batch of pulp cooked during the season be made from a measured quantity of tomatoes or tomato juice, and cooked to the same point on the measuring stick, the pulp will not all be of the same specific gravity, because tomatoes are very watery at some seasons of the year and very firm and solid at other times. The watery tomatoes will make a thin pulp, and the firm tomatoes will make a heavier pulp. Cooking a Definite Length of Time Cooking for a certain length of time is not dependable because the steam pressure is not always the same, the coils do not always condense the pulp with the same efficiency, and the character of the tomatoes varies during the season. With this method it is also necessary to start with a definite quantity of tomato stock for each batch. Determining Specific Gravity by Weight The third method—that of determining the specific gravity by weight—is used as commonly as any of the others. The specific gravity of pulp merely means the comparison between the weight of a definite volume of the pulp and the weight of the same volume of water at the same temperature. If pulp has a specific gravity of 1.035, that means that a gallon of it is 1.035 times as heavy as a gallon of water. The determination, as carried out in the cook room, is made with a small trip balance, a set of weights, and a copper flask which is tin lined. The weight of the empty flask is taken. Then the weight of the flask filled to the top with boiling water is taken. The difference between these two weights is the weight of water at the boiling point which the flask contains. When the boiling pulp approaches the finishing point, the flask is filled to the top with the boiling pulp. This should be done rapidly, as the pulp cools quickly, and as it cools, decreases in volume. The weight of the flask filled with pulp at the boiling point is taken. This weight, minus the weight of the empty flask, equals the weight of pulp at the boiling point which the flask contains. You now have the weight of boiling water the flask contains, and the weight of boiling pulp the flask contains. Divide the former into the latter, and the result (the quotient) is the specific gravity. For example, if the water weighs 1,000 grams, and the pulp weighs 1,035 grams, the specific gravity is 1.035. If the specific gravity of cold pulp is taken, then cold water of the same temperature must be taken as the comparison. The weight of cold pulp must not be compared with the weight of hot water, and vice versa. Objections to Weighing Method