Inner-tubes are the inflatable parts between the tire and the metal parts of the wheel. They are invisible apart from their valves that protrude through the wheel-rims. There are three valve types in use; Schrader valves, Presta valves, and the lesser used Dunlop valves. Refer to the adjacent image for examples.
The word papyrus /pÉËpaÉªrÉs/ refers to a thick paper-like material made from the pith of the papyrus plant, Cyperus papyrus. Papyrus can also refer to a document written on sheets of papyrus joined together side by side and rolled up into a scroll, an early form of a book.The plural for such documents is papyri.apyrus is made from the stem of the papyrus plant, Cyperus papyrus. The outer rind is first removed, and the sticky fibrous inner pith is cut lengthwise into thin strips of about 40 cm (16 in) long.
Books have been around for thousands of years. When ancient civilizations first started developing writing systems, they would write on just about anything, from stone to tree bark. Ancient Egyptians were the first to use paper-like materials, called papyrus, which they made by pounding flat the woven stems of the papyrus plant. It was not long before the ancient Egyptians began gluing together papyrus sheets to form scrolls, which were the first steps toward books as you know them.