If we now consider the case of any instrument of labor during the whole period of its service, from the day of its entry into the workshop, till the day of its banishment into the lumber room, we find that during this period its use-value has been completely consumed, and therefore its exchange-value completely transferred to the product. For instance, if a spinning machine lasts for 10 years, it is plain that during that working period its total value is gradually transferred to the product of the 10 years. […]
Yet another interesting phenomenon here presents itself. Suppose a machine to be worth £1000 and to wear out in 1000 days. Then one thousandth part of the value of the machine is daily transferred to the day’s product. At the same time, though with diminishing vitality, the machine as a whole continues to take part in the labor-process. Thus it appears, that one factor of the labor process, a means of production, continually enters as a whole into the process, while it enters into the process of the formation of value by fractions only. […]
We have seen that the means of production transfer value to the new product, so far only as during the labor process they lose value in the shape of their old use-value. The maximum loss of value they can suffer in the process is plainly limited by the amount of the original value with which they came into the process, or in other words, by the labor-time necessary for their production. Therefore, the means of production can never add more value to the product than they themselves possess independently of the process in which they assist. However useful a kind of raw material, or a machine, or other means of production may be, though it may cost £150, or, say, 500 days’ labor, yet it cannot, under any circumstances, add to the value of the product more than £150. Its value is determined not by the labor-process into which it enters as a means of production, but by that out of which it has issued as a product. In the labor-process it only serves as a mere use-value, a thing with useful properties, and could not, therefore, transfer any value to the products, unless it possessed such value previously.
Marx, Capital Volume 1 (Progress Publishers, 1887), p. 144-145
Let us assume, that some invention enables the spinner to spin as much cotton in 6 hours as he was able to spin before in 36 hours. His labor is now six times as effective as it was, for the purposes of useful production. The product of 6 hours’ work was increased six-fold, from 6 lbs to 36 lbs. But now the 36 lbs of cotton absorb only the same amount of labor as formerly did the 6 lbs. One-sixth as much new labor is absorbed by each pound of cotton, and consequently the value added by the labor to each pound is only one-sixth of what it formerly was. On the other hand, in the product, in the 36 lbs of yarn, the value transferred from the cotton is six times as great as before. By the 6 hours’ spinning, the value of raw material preserved and transferred to the product is six times as great as before, although the new value added by the labor of the spinner to each pound of the very same raw material is one-sixth of what it was formerly. This shows that the two properties of labor, by virtue of which it is enabled in one case to preserve value, and on the other to create value, are essentially different. On the one hand, the longer the time necessary to spin a given weight of cotton into yarn, the greater is the new value added to the material; on the other hand, the greater the weight of the cotton spun at a given time, the greater is the value preserved, by being transferred from it to the product.
Marx, Capital Volume 1 (Progress Publishers, 1887), p. 143