Some manufacturers who desire to work with the simplest possible methods, even at the sacrifice of a high degree of control over the concentration of their products, measure the volume of cyclone juice introduced into the evaporating tank; and when it is believed that the concentration is sufficient, measure the depth of the evaporated product in the tank, the steam being momentarily turned off for that purpose and the measurement being taken after the foam subsides. This method was outlined in detail in a trade paper article published from this laboratory in 1918. The method is somewhat inaccurate, because it is based on the measurement of cyclone juice as it flows from the cyclone and which therefore contains a large amount of air. This air materially increases the volume of the pulp and consequently the amount of finished pulp calculated from the volume of cyclone juice containing this air is greater than can actually be obtained. Some manufacturers of pulp have found the method practicable, however, by making a correction based on factory experience on the amount of pulp which the method indicates should result from the evaporation of each bath. This method also calls for the use of measuring tanks, which many manufacturers do not have and do not care to provide. The method is therefore not repeated here, but the laboratory has a number of reprints of the trade paper article which are available to any who desire more detailed information regarding the matter. The following method has been found more accurate and more convenient than the one mentioned above. It has the special advantage that it is based on the examination of the cyclone juice after the juice has been heated to a sufficient extent to “break” the foam. In using this method, the manner in which the cyclone juice is prepared is immaterial. The tomatoes may be broken by steam or mechanical breaker and may be cycloned hot or cold. The steam may be turned into the coils as soon as they are covered and the cyclone juice may run into the evaporating tank until the tank is filled. Finally, when the last of the cyclone juice is added and the contents of the tank are boiling vigorously, the steam is momentarily turned off. The volume is then determined by means of a gauge stick and a sample is withdrawn, filtered and the specific gravity or degrees Brix determined as described on page 50. The extent to which evaporation must be continued to secure pulp of the desired specific gravity is determined by Table 9. This table gives in the first four columns the specific gravity of the partially concentrated pulp taken from the evaporating tank, the per cent of solids of the same, the specific gravity of the filtrate and the Brix reading of the filtrate. In order to use the tables, it is only necessary to make use of one of these columns.