Even these figures do not fully represent the facts, for they include considerable numbers of mills of the older sort, where spinning and weaving are carried on together. Taking the more highly specialised spinning mills in the Oldham district, the average is stated at 65,000, while the largest mills have as many as 185,000 spindles. So also the average number of power-looms in the North Lancashire district is placed at 600, the largest number in a single business amounting to 4500.[106] "Again, the cost of a steamship is perhaps equivalent to the labour of ten years or more of those who work her, while a capital of about £900,000,000 invested in railways in England and Wales is equivalent to the work for about twenty years of the 400,000 people employed on them."[107] This growth in the unit of capital is, as we perceive, largely due to the establishment of large and expensive machinery and other plant as a leading feature in modern production. The fact that modern methods are largely instrumental in increasing the quantity of products might lead us to suppose that the growth of the raw material or circulating part of the capital of a business would correspond with the growth of fixed forms of capital. This, however, is not the case. In the most highly organised machine industry an increasing proportion of the economy goes into the improved methods of manipulating material so as to prevent waste, and by improved quality of work and elaboration of manufacture to get a larger net amount of product out of a given quantity of raw material. In cotton-spinning, for example, since 1834 the waste of raw material has been reduced from 1/7 to about 1/10; inferior material, once useless, is now mixed with better stuff; and more important still, modern machinery has, by adapting itself to the spinning of finer yarn, effected great saving in the quantity consumed by each spindle. In many other industries we shall find this same process going on, whereby the proportion of capital which consists of raw material is reduced, and the proportion which consists in machinery and other fixed capital enhanced. The growth of the unit of capital in the developed modern manufacturing business entails also a growth in the unit of labour, though not a corresponding growth. The number of employees in a business is larger in proportion as the business passes into the stage of highest industrial organisation. In the United States in 1880 it was estimated that the average number of employees in a manufacturing business for the whole country was a little less than 11, but in the chief manufacturing states of Massachusetts, Connecticut, and Rhode Island it was about 25, while in Pittsburg, the great centre of iron industry, it was more than 33.