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Rh seen in Fig. 72, using a byproduct from the manufacture of rice syrup for cementing. In Nanking we watched with much interest the manufacture of charcoal briquets by another method. A Chinese workman was seated upon the earth floor of a shop. By his side was a pile of powdered charcoal, a dish of rice syrup byproduct and a basin of the moistened charcoal powder. Between his legs was a heavy mass of iron containing a slightly conical mold two inches deep, two and a half inches across at the top and a heavy iron hammer weighing several pounds. In his left hand he held a short heavy ramming tool and with his right placed in the mold a pinch of the moistened charcoal; then followed three well directed blows from the hammer upon the ramming tool, compressing the charge of moistened, sticky charcoal into a very compact layer. Another pinch of charcoal was added and the process repeated until the mold was filled, when the briquet was forced out.

Fig. 72.—Charcoal balls briquetted with rice water or clay, for use as fuel.

By this simplest possible mechanism, the man, utilizing but a small part of his available energy, was subjecting the charcoal to an enormous pressure such as we attain only with the best hydraulic presses, and he was using the principle of repeated small charges recently patented and applied in our large and most efficient cotton and hay presses, which permit much denser bales to be made than is possible when large charges are added, and the Chinese is here, as in a thousand other ways, thoroughly sound in his application of mechanical principles. His