Next to agriculture, the iron-works and machine-factories gave employment to the greatest number; in fact, if we take not the temporary employment of a large number of men, but the total number of labour-hours devoted to the work, as our measure, then these latter industries employed much more labour than agriculture. And this is not to be wondered at, for all the associations needed machinery in order to carry on their work to the best advantage. In other countries, where the wages of labour and the profit of labour are fundamentally different things, there is a fundamental distinction between the profitableness of a business and the theoretical perfection of the machinery used in it. In order to be theoretically useful a machine must simply save labour--that is, the labour required for producing and working the machine must be less than that which is saved by using it. The steam-plough, for example, is a theoretically good and useful machine if the manufacture of it, together with the production of the coal consumed by it, swallows up less human labour than on the other hand is saved by ploughing with steam instead of with horses or cattle. But the actual profitableness of a machine is quite another thing--out of Freeland, we mean, of course. In order to be profitable, the steam-plough must save, not labour, but value or money--that is, it must cost less than the labour which it has saved would have cost. But elsewhere in the world it by no means follows that it costs less because the amount of labour saved is greater than that consumed by the manufacture of the steam-plough and the production of the coal it uses. For whilst the labour which the improved plough saves receives merely its 'wages,' with the bought plough and the bought coal there have to be paid for not only the labour required in producing them, but also three items of 'gain'--namely, ground-rent, interest, and undertaker's salary. Thus it may happen that the steam-plough, between its first use and its being worn out, saves a million hours of labour, whilst in its construction and in the total quantity of coal it has required, it may have consumed merely 100,000 hours of labour; and yet it may be very unprofitable--that is, it may involve very great loss to those who, relying upon the certainty of such an enormous saving of labour, should buy and use it. For the million hours of labour saved mean no more than a million hours of _wages_ saved; therefore, for example, 10,000£, if the wages are merely 1£ for a hundred hours of labour. For the construction of the plough and for the means of driving it 100,000 hours of labour are required, which alone certainly will have cost 1,000£. But then the rent which the owners of the iron-pits and the coal-mines charge, and the interest for the invested capital, must be paid, and finally the profits of the iron-manufacturer and the coal-producer. All this may, under certain circumstances, amount to more than the difference of 9,000£ between