Silk
Silk moths lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed fresh mulberry leaves. After about 35 days and 4 moltings, the caterpillars are 10,000 times heavier than when hatched and are ready to begin spinning a cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head in a pattern. Two glands produce liquid silk and force it through openings in the head called spinnerets. Liquid silk is coated in sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2–3 days, the caterpillar spins about 1 mile of filament and is completely encased in a cocoon. The silk farmers then heat the cocoons to kill them, leaving some to metamorphose into moths to breed the next generation of caterpillars. Harvested cocoons are then soaked in boiling water to soften the sericin holding the silk fibers together in a cocoon shape. The fibers are then unwound to produce a continuous thread. Since a single thread is too fine and fragile for commercial use, anywhere from three to ten strands are spun together to form a single thread of silk.
Silk industry of Cheshire
Silk is a naturally produced fibre obtained from many species of the silk moth. In 1700 the favoured silk was produced by a moth (Bombyx mori), that used it to spin a closed cocoon to protect her larvae. These fed on the mulberry leaf which was grown in Italy. Silk fibres from the "Bombyx mori" silkworm have a triangular cross section with rounded corners, 5-10 μm wide. The silk is a protein called fibroin and it was cemented in place by the use of a gum, another protein called sericin. The cocoons were harvested and placed in troughs of hot water that dissolved the gum and allowed the single thread to be wound into a skein.