Compressed Air and Hose. In rubber factories hose is removed from the iron mandrels by forcing a current of air under fifty to sixty pounds pressure between hose and mandrels, thereby inflating the hose, and permitting it to be easily slipped off. The hose manufacturer also uses compressed air fer testing his product, a test as high as 1000 pounds pressure per square inch being demanded on some varieties. A new plan which has lately been adopted in silk-mills is the spraying of solutions on silk ribbon by means of compressed air under forty pounds pressure. This system is highly successful, as it possesses many advantages over old methods and is rapidly being introduced by the manufacturers.