James Hargreaves' invention of the spinning jenny came at just the right time — a time of technological innovation in looms and weaving in Great Britain.
He invented the "jenny" in 1764. His insight was that the spindles on the spinning wheel didn't have to be horizontal, but could be placed vertically in a row — that allowed room for more of them.
Before Hargreaves, Spinning Was a Cottage Industry
Before Hargreaves, wool, flax, and cotton thread were created by spinners, people who worked at home on a spinning wheel, in a true "cottage industry."
The raw material was cleaned and carded, then turned into roving, a slightly twisted strand of fibers. It took three carders to provide the roving for one spinner, and up to three spinners to provide the yarn for one weaver. The roving was put over a spinning wheel, where it was twisted tighter into thread, which collected on the spinning wheel's spindle.
Hargreaves' design consisted of a frame with eight wooden spindles at one end. Eight rovings were passed through two horizontal bars of wood that could be clasped together, while the spinner turned a wheel that caused the spindles to turn and the thread to be wound around them.
The name "jenny" most likely comes from the English slang for "engine." Hargreaves' first jenny had eight side-by-side spindles controlled by a single wheel and a belt. Later models had up to 120 spindles. Hargreaves built several models and started to sell them to locals.
The spinning jenny was small enough and light enough to be operated by a single woman or child if need be.
Reaction to the Spinning Jenny
Response to the spinning jenny was swift. Because each machine did the work of eight people, and increased production led to a drop in prices of yarn, the spinners were up in arms. In 1768, a group of spinners broke into Hargreaves' house and destroyed his machines.
Hargreaves responded by relocating to the city of Nottingham in 1768. There, he found a business partner in Thomas James, and the two men set up a mill to supply hosiery makers with yarn. On July 12, 1770, Hargreaves took out a patent on a 16-spindle spinning jenny.
Hargreaves, then, sent out the 18th-century version of a "cease and desist" letter to manufacturers who were using the jenny, but he ultimately lost the court case when his patent application was denied. The courts found that Hargreaves had produced and sold too many machines before filing for the patent.
The Jenny and the Industrial Revolution
The textile industry was the tip of the spear of the industrial revolution. While an eight-spindle spinning jenny could be used at home, as the machines grew to 16, 24, and eventually 80 and 120 spindles, they moved out of homes and into factories.
The yarn produced by the jenny wasn't very strong until Richard Arkwright invented the water-powered "water frame," which created a yarn that was harder and stronger than that produced by the spinning jenny. The spinning jenny was used in the cotton industry until around 1810 when the spinning mule replaced it.
At the same time as the invention of the spinning jenny, British chemists were refining the processes for bleaching, dyeing, and calico-printing cloth. This gave a further boost to the British textile manufacturing industry.