Martin Galloway, age 12, of Lowell, Mass., for his question:

WHAT IS MANILA ROPE?

Rope is a strong line or cord. About nine tenths of the fibers that are made into rope come from the abaca plant and the agava, or century plant. Ropes made from abaca fibers are known as Manila, and ropes manufactured from agave fibers are called sisal.

Manila is a strong, hard fiber that comes from the leaf stems of the stalk of the abaca. The abaca plant looks much like a banana tree. The fiber gets its name from Manila in the Philippines where the abaca plant grows.

Manila has great natural resistance to wind, rain and sun. The tough, sheathlike protection of the fiber cells of the abaca plant makes Manila rope very strong.

Manila rope also is resistant to rubbing. These qualities make Manila valuable for use on ships. Manila fiber is preferred for most kinds of rope that receive long, hard usage.

Sisal, a hard fiber, is about three fourths as strong as Manila. But it is the most widely used substitute for Manila.

Sisal is a whiter, shinier fiber than Manila. It comes from the leaf of the agave plant, which grows in the West and East Indies and in parts of Africa. Sisal also is made into tying twines for use in factories and stores.

Rope can also be made from henequen, true hemp, jute and coin. Henequen is much like sisal although not so strong. It grows in Mexico and as rope is used mostly to make a binder twine used for agricultural purposes.

True hemp comes from many European and Asian countries while jute is a fiber that comes from India. In rope, both have less strength than Manila. Coir, which comes from the outer husk covering of the coconut, is grown in India and used chiefly to make a rope that is water resistant.

Lately nylon rope has replaced many other types of rope for many uses because it is stronger, lighter in weight and resistant to mildew.

Fibers are made into rope by machinery. They come to the factory in bales weighing about 275 pounds.

First the fibers are prepared by separating them, laying them straight and combing them into ribbons. Combing reduces the width of the ribbon for spinning into yarn.

Two or more yarns are twisted into strands. Then the strands are twisted or laid together to form the rope. Most ropes are made of three strands. The number of yarns varies.

Strength of rope depends on its size and the material from which it is made. A Manila rope that measures an inch and a half around can hold a weight of 2,650 pounds. A Manila rope measuring seven inches around can lift 41,000 pounds.

Wire ropes are made by twisting a number of individual wires together to form a strand. The strands are then twisted around a hemp core. They are widely used for cables, for ship rigging and in operating derricks of oil and salt wells. They are also extensively used in industry.