Crushing the tomatoes without cycloning them is a very good method where the tomatoes are going to be made into pulp or puree, as the finishing machine will convert the crushed cooked tomatoes into a very smooth product. Where catsup is to be made direct from the tomatoes, however, cycloning is to be preferred to crushing. If the final product is to be soup, cycloning is necessary. This will be discussed further in the chapters on catsup and soup. When a crusher is used it takes the place of the cyclone or pulp machine, although it performs an entirely different kind of an operation, and the tomatoes go through exactly the same process as in cold pulping, except that instead of removing the seeds and skins from the tomatoes before cooking, the tomatoes are chopped very fine and conveyed to the cooking kettles—seeds, skin and all. It is obviously somewhat harder to gauge the finishing point of a batch of pulp where the skins and seeds are present, however a little practice largely eliminates this difficulty, and there is always the method of determining the specific gravity by weight to fall back on. The seeds and skins will not interfere with making the specific gravity test as it is usually carried out in the cook room with a large copper flask, small trip balance, and set of weights. Conveying to Kettle If the plant is so arranged that the pulped or crushed tomatoes can be conveyed to the cooking kettles by gravity, that is an advantage, as it does away with a pump and someone to tend to it, and the fewer the pumps, the better; however, in most plants it is necessary to pump the pulped or crushed stock into the cooking kettles. Unless the plant consists of several floors and the tomatoes start at the top and come out as finished pulp at the bottom, or the plant is built on a terraced plan, as one plant is in Indiana, which is built on the side of a hill, it is necessary to do a certain amount of pumping. An ordinary pump will not do, as there would be contamination by iron, and considerable rusting, while the pump was idle, of those parts of the pump with which tomato juice comes in contact, this rust to be carried along with the tomato juice the first time the pump is used again. The rotary pump constructed partly of bronze or nickel is very good for this purpose, and offers as little opportunity for metallic contamination as any pump does.