Question

The international demand of indigo was affected by the discovery of__________.
A- Flying shuttle
B- Spinning Jenny
C- Sewing machine
D- Synthetic dye

Answer 1

Hint
Indigofera tinctoria is a species of plant from the bean family that was one of the original origins of indigo dye, also called true indigo. The name of Indigo gives its origin: it literally means 'Indian' or from India.' But we now know that indigo is also native to the tropical zones in Africa and China, in addition to India.

Complete answer:
Our ancestors in India, East Asia and Egypt, and possibly the Maya, used the blue dye derived from the Indigofera Tinctoria plant to dye their clothes as early as more than 5,000 years ago.

As a consequence, the market for indigo has remained as high as ever. Nevertheless, with demand, the pressure to find cheaper alternatives to the complicated manufacturing process of plant dye has increased exponentially.

The great American Gold Rush and the subsequent burgeoning market for work clothes further expiated this, which in turn skyrocketed the US demand for indigo.
In an attempt to produce artificial indigo, German chemist Adolf von Baeyer performed his first experiments at the end of the 1860s.

He went on to develop a synthetic production process over the following years, which went like this, severely simplified: beginning with the amino acid aniline, he created the plant ash oxindole. With the aid of zinc dust, this is reduced into indol, which in turn, is reduced into its derivative isatin.

When Baeyer eventually managed to extract the isatin completely, he discovered the first completely synthetic alternative to natural indigo, which had equally outstanding dye properties.

In the meantime, demand for the deep blue dye soared to new heights. Although the Gold Rush was nearly over by this time Europe and America's rising industrialization with its manufacturers, factories, mines, shipbuilding docks, and oil production meant that unprecedented numbers of workers suddenly needed durable workwear.

Jacob W. Davis and Levi Strauss invented a pair of work trousers in 1873 that would continue to dominate the globe. With rivet reinforced pockets, jeans made of sturdy denim quickly become fast favourites among hard-working men.

Thus, indigo blue, once a privilege reserved for royalty, eventually completed its transformation into the distinctive mark of the working classes by the aristocracy.

Therefore the correct answer is D

Note
Most of the dye today is synthetic, but there is still natural dye from the indigo plant available. It is sold in Indonesia as a natural colouring, where it is known as tarum and in Malaysia as nila.