Many people use the term machine and tool interchangeably.  So what is the difference.  According to Marx all machinery consists of three types of bits: the motor mechanism, the transmitting mechanism, and the moving tools.  The motor mechanism is what puts movement into the parts of the machine, the transmitting mechanism, such as toothed wheels and pulleys etc. The tool is that part of the machine that moves, due to the other two parts, and helps to produce a given commodity.  A tool in this sense is different from the tool of a workman.  A workman might use a hammer or a chisel but they are tools not machinery.  If, however, some machine was invented for hammering nails than a "hammer" would in effect become a machine.  The difference between a machine and a tool thus lies in the first two parts that go to form a machine, the motor mechanism and the transmitting mechanism.

For Marx the intention of machinery and its application to the process of production is not about lightening the workers toil or increasing the wealth of nations. Marx writes:

"John Stuart Mill says in his Principles of Political Economy: 'It is questionable if all the mechanical inventions yet made have lightened the day's toil of any human being.' That is, however, by no means the aim of the capitalistic application of machinery. Like every other increase in the productiveness of labour, machinery is intended to cheapen commodities, and, by shortening that portion of the working day, in which the labourer works for himself, to lengthen the other portion that he gives, without an equivalent, to the capitalist. In short, it is a means for producing surplus-value."

Before we can examine how the rate of surplus-value is increased by the application of machinery it is first necessary to understand the concept of surplus-value. The concept of surplus-value is perhaps the most important, and distinguishing, feature of Marxist economics. In order, however, to understand what surplus-value is we will first have to outline the labour theory of value.

According to Marx every commodity has two features: use-value and exchange-value. The use-value of a commodity referred to the fact that it has some sort of use, that is, it meets some sort of want. The commodity that has no use, that meets no want, has no use-value and therefore no exchange-value. The exchange-value of a commodity refers to the ratio at which one commodity exchanges with another. Every commodity, when taken in certain proportions, can be exchanged with any other commodity. Commodities, however, tend to exchange at certain ratios, the question Marx wanted to answer was why? There must be something common to both commodities being exchanged, something in common, that regulates exchange.

For Marx the answer to this question was not to be found in the material body of commodities. There was nothing about a chair that dictated that it should be exchanged for a certain number of tables, an apple does not demand so much flour be exchanged for it. The answer to this question was to be found in the fact that both commodities, be they what they may, are products of human labour. All have been produced by the expenditure of labour-power, by labour. The ratio at which commodities exchange is therefore governed by the amount of labour time embodies within them, or more accurately, the labour time socially necessary in their production.

But this still does not explain where the profits of the capitalist come from? If in the sphere of exchange equals are exchanged, commodities containing roughly similar amounts of labour embodied within them, then from where does profit come from. Some economists thought that the profit of the capitalist came from waiting, they got a delayed return on their investment. Yet the working-class could wait and they would never get a single penny of profit. For Marx the profit of the capitalist derives from the fact that the worker is paid not for their labour, as it appears, but for their labour-power. The labour-power of the worker is simply their capacity to labour.

The value of labour power is, like all other commodities, determined by the labour time necessary to produce this special commodity. But what is required to produce this special commodity called labour-power? What is needed are those commodities that sustain the life of the labourer and enable them to reproduce their labour-power every day, and to reproduce the next generation of workers, their children. Of course there are some other commodities which have been won by the proletariat, and in certain societies, and even within the working-class itself, these will vary. Thus, the working-class get more than just subsistence wages, at least, in most societies that comprise the First World this is now the case.

Surplus-value is simply this: the difference between the value (labour time) of the labour-power employed and the value (labour time) of the products produced by this labour power in motion, that is labour. To put it slightly differently, it is the difference between the value of the commodities at the beginning of the production process and the values at the end of the process. The increment in their exchange-value Marx calls surplus-value.

Now that we know what the labour theory of value, and the theory of surplus value are we are in a better position to examine how machinery increases surplus-value. Machinery can increase two forms, or forms of extraction, of surplus-value. Machinery can both increase absolute and relative surplus-value.
 
 

The surplus-value of the capitalist can be increased by lengthening the duration of the working-day. The longer the worker works so the more surplus-value they produce and so the more profit they make. If in five hours they produce the equivalent in value (labour time) embodied in the products of their labour as the value of their labour-power so if they work 5 more hours they produce five hours of surplus-value. If the capitalist gets them to work an extra hour then the surplus-value produced is one hour greater. The introduction of machinery allowed for, and indeed created under the conditions of capitalism, the situation in which the length of the working day actually began to increase. In order to get as much time as possible many capitalists stooped to the most disgusting methods. Marx in his book Capital relates some of the documented examples of this barbarity:

"G. Alspen (the boy's father): 'That boy of mine...when he was 7 years old I used to carry him on my back to and fro through the snow, and he used to have 16 hours a day (of work!)...I have often knelt down to feed him as he stood by the machine, for he could not leave it or stop..."

Machinery did not just enable absolute surplus-value to be increased it also increased relative surplus-value, or, the rate of surplus-value. With absolute-surplus value the rate of surplus-value does not increase. With every hour worked the mass of surplus-value may increase but the rate at which it is produced does not increase. One hour more may produce £1,000 more of surplus-value for the capitalist but the rate has remained the same. The general application of machinery allows for an increase in the rate of surplus value. But how?

Machinery allows for this increase because in most cases the introduction of machinery makes production much more efficient. By this what I mean is that more commodities can be produced in the same, or perhaps less, time than before. Marx gives the example of the hand weavers. When power-looms were introduced the production time for a given length of cloth was halved by the introduction of the power loom. By decreasing the value of commodities in general so the value of labour-power, and thereby the workers wage, was lowered. The workers wage we should remember is more than just so much money. This money has to be converted into certain commodities in order that the worker might live, in the full sense of the word. If such commodities are cheapened so too is the exchange-value of labour-power. The rate of surplus-value is thus increased by the general application of machinery to production.

The rate of surplus-value was also increased in another way my machinery. As we learnt earlier machinery allows for a lengthening of the working day because work became less a matter of sheer force. The machine not only allowed this increase in the working day it also allowed for the employment of both children and women. Marx writes:

"In so far as machinery dispenses with muscular power , it becomes a means for employing labourers of slight muscular  strength, and those whose bodily development is incomplete, but whose limbs are all the more supple. The labour of women and children was, therefore, the first things sought for by capitalists who used machinery..." (Capital)

"The value of labour-power was determined, not only by the labour-time necessary to maintain the individual adult labourer, but also by that necessary to maintain his family. Machinery, by throwing every member of that family on the labour-market, spreads the value of the mans labour-power over his whole family. It thus depreciates his labour-power. To purchase the labour-power of a family of four workers may, perhaps, cost more than it did formerly did to purchase the labour-power of the head of the family, but in return, four days labour takes the place of one, and their price falls in proportion to the excess of the surplus-labour of four over the surplus-labour of one..."

We should remember that Marx was not criticizing machinery itself. The machine is a mere thing, an object, possessing no volition. It is the capitalist class, motivated by the endless chase after profit that sets the worker to work not the machine. The machine produced the beneficial situation in which there is the potential for the necessary working day to be decreased and at the same time for people to enjoy much greater material wealth. Unfortunately under the system of capitalism the machine simply serves to increase the individual capitalists profit and to lengthen the hours of work. It was capitalism and the actions of the capitalist class that Marx criticized, not the machine.