Final concentration of the ketchup is controlled in the same manner as for pulp, either by a gauged tank or by specific gravity determination. If we start, therefore, with a given volume of partially concentrated cyclone juice and determine the solids present, we can in every case quickly ascertain from the appropriate table the number of gallons of finished product we should obtain, and the gauge stick or attached gauge glass will indicate when to stop evaporation in the tank. One advantage of measuring the original volume at the boiling temperature is that no temperature corrections are necessary, as both the initial and final temperature measurements are approximately the same. The final concentration may be controlled, as stated above, by determining the specific gravity of the finished product by one of the methods given under pulp (see page 33 and following). The determination of specific gravity at this point will probably give more accurate results than the use of a gauge stick, and is to be recommended for use with the finished product, provided the added constituents have been standardized. The method described on page 42 for determining the specific gravity of hot tomato pulp, may be used for obtaining the per cent of solids in the boiling cyclone juice in place of the Brix spindle reading on the filtrate. Table 11 for controlling the concentration of finished ketchup is based on the idea that there shall be a definite volume of partly concentrated pulp in the tank when the inflow of cyclone juice is stopped and the sample is taken for analysis. In this respect, this method of controlling the concentration of ketchup varies from the method described on page 54 for the control of the concentration of tomato pulp. It is sometimes convenient to secure this definite volume by filling the tank to a greater height than is desired and evaporating until the desired volume is secured. When this point is reached the sample of pulp is taken for specific gravity and steam is again turned on the tank. The Abbé refractometer may also be used for controlling the final concentration of the ketchup. This provides a very simple and quick method for determining the percentage of solids. It requires but a few drops of the filtered liquor from the ketchup to make the determination. The reading may be taken and the calculation made in one or two minutes’ time by use of Tables 13 and 14. The table for calculating the solids from the refractometer reading is Geerlig’s table for dry substance in sugar-house products, and is taken from the Methods of the Association of Official Agricultural Chemists, 1919. The entire table is not given but only the range over which it might possibly be desired to use it in the control of the manufacture of ketchup.