In a modern cotton factory there are three departments of labor, carding, spinning, and weaving; and we have now to consider briefly these three processes. The purpose of carding is to clean the cotton and lay the fibres in a uniform direction. This was at first accomplished by hand, the implement employed being little different from an ordinary comb; later an improved device was used consisting of a pair of large wire brushes. This, we must observe, was a primitive operation, and the amount of cotton which one person could thus prepare for spinning was very small. We have already seen that the invention of the fly-shuttle so increased the demand for yarn that ingenious men were induced to make mechanical experiments for the purpose of supplying this demand—experiments which, in the end, led to the invention of the spinning-frame. The spinning-frame, in turn, increased the demand for carded cotton and skillful mechanics again set about to meet this new requirement, and the result was the building of the carding-engine. This invention was not made at once, nor by any particular individual; but was the result of a number of improvements made at different times and by different persons. One of these men was Thomas High, the inventor of the spinning-jenny; another was James Hargreaves who so improved the jenny that he is commonly called the inventor of it; and finally, Richard Arkwright himself took the crude machine devised by these men and perfected it. Thus it came about that the modern carding-engine as well as the spinning-frame, was made of practical value by this much-enduring, much-inventing barber. The invention of the fly-shuttle, as we have seen, led to an increased demand for yarn, and this demand was further augmented about the year 1760 when the Manchester merchants began to export cotton goods in considerable quantities to Italy, Germany, and the North American colonies. It was then no uncommon thing for a weaver to walk three or four miles in the morning, and call on five or six spinners, before he could collect yarn enough to serve him for the remainder of the day.