The pipe used for the conveying of this tomato stock should by all means be enamel lined. Enamel lined pipe, if properly made, will last for many years without chipping or cracking. Just how long it will last on the average I cannot say, but I have often taken down lines of enamel lined pipe that have been in use for several years, and it looked practically as good as new. The flanged pipe with flanged fittings is better than that with the ordinary screw ends, as it makes practically a continuous white tube without any pipe threads in which molds, yeasts, and bacteria can lodge and multiply. Wooden troughs are still used in many plants for conveying tomato juice and pulp, but they are a relic of the old days, and have no place in the modern pulp or catsup plant. Wooden troughs are hard to keep clean, they mold very quickly after they become damp, they are open to contamination from ceilings and roofs which aren’t always in good condition, and they are usually wasteful. It will pay any packer who still uses even a few wooden troughs to invest in enamel lined pipe. Wooden pipe is also unsanitary for this purpose, as mold grows in it and clings so tightly to the porous, damp surface that it cannot possibly be flushed out. Value of Pumice This chapter, which deals principally with cycloning, seems to be a fitting place to discuss the value of the pumice which comes as a waste product from the cyclone. Although it has been repeatedly demonstrated by chemical analysis that this pumice or tomato waste is a valuable by-product, every time the question has come up of its utilization and preparation into a salable product or products, the decision has been that the expense involved would be too great to make it pay. This by-product is profitably handled in Italy, producing an oil of commercial value, and an oil cake which is used for stock feed; however, the conditions in Italy and in this country are very different. In the Parma district of Italy there are forty factories very close together, and little expense is involved in bringing the waste to a central point where enough of it can be had to keep a drying outfit and an oil press or oil extraction outfit busy. Labor is also very cheap and plentiful, and there is a ready market for the product, the oil being used as a soap stock, and the oil cake finding ready sale as a stock feed. In this country, however, there is not enough waste at even one of the largest plants to pay for the operation of a drying outfit and the pulp plants are so scattered that hauling or shipping charges to a central point would be expensive. Furthermore, labor is scarce and expensive.