7: Exceeding Human Capabilities
It has been mentioned in passing that the tools and machines of manufacturing are capable of exerting forces greater than human muscle, and in performing operations that are too delicate for the human touch - and this will be explored further.
He mentions the use of rope and harness to concentrate the power of many men, or even many animals. A wagon that was to heavy for a single horse could be drawn by two or more horses harnessed together and a weight too heavy for a man to lift can be hefted by two or more men who coordinate their efforts. However, this approach is limited.
The first limitation is the size of the creatures involved. It is not possible to have a wagon drawn by a hundred horses, nor for more than two or four men to work together to life a heavy object that is a foot long. The second limitation is in the difficulty of coordination. In order for their forces to be combined, they must act in perfect simultaneity - the horses must pull together in step and the men must lift all at once. This is exceedingly difficult and there is a diminishing return on labor: eight horses have not eight times the power of a single horse, but perhaps of six, simply because they do not walk in perfect step with one another. And twelve horses yoked together may also have the power of only six, because the asynchronous movements work against one another.
For human workers, there is the ability to communicate and coordinate by means of orders. Horses cannot be made to walk in step with one another, but human beings can do so - and their motions can be coordinated by the use of sound. The drummer on a galley uses his drum to signal the men to coordinate each motion - to lift the oar, to pull the oar, etc. - but this has limited efficiency. Depictions of slaves in ancient Egypt have been depicted moving large blocks of stone, directed by the orders of their overseers who. According to hieroglyphic illustrations, would clap their hands to singal the men to move.
Signaling of this nature is still used in modern manufacturing - bells, whistles, and other devices provide an auditory cue to which men coordinate their motions to large numbers of men across great distances. However, the use of machines concentrates force into a single mechanism of great power: the operation of a hydraulic crane can lift enormous parcels without the need for coordination - and when coordination is needed, it can be effected mechanically with great precision. A single lever may control two cranes, and they will be perfectly synchronous in their operation.
Babbage marvels a bit at the use of steam power and pistons - ho a rod within a cylinder can exert great force if it is lifted by the pressure of steam in a chamber, and how this simple device can operate at high speed by valves that trap and release steam pressure. (EN: As usual, it is overly detailed and a bit unnecessary to the present-day reader.)
He then turns to operations that require precision and delicacy greater than humanly possible. For example, the task of sorting pearls or peas is nearly impossible for humans to perform accurately and with speed - our sight and even touch is not sufficient to quickly distinguish minute differences in the circumference of small objects and it takes time to assess each one and compare it to others. The simple use of a stack of boxes separated by screens of diminishing fineness makes the process fast, simple, and precise on a level that human beings cannot accomplish without the assistance of tools.
The process of grinding large particles into smaller ones with varying degrees of granularity is also difficult using a mortar and pestle, but the use of a mechanical grinder does this with speed and precision. Likewise, purifying water by removing the fine particles of mud suspended in it is entirely impossible to do with the human hand, but the use of filters and pressure can clarify muddy water in short order. Or removing the seeds from cotton - before the invention of the cotton gin, this task was done by hand in a very inefficient manner: not only did it take considerable time to manually pick out seeds, but a great deal of usable fiber was wasted by the clumsiness of human hands.
(EN: And as usual, there are more examples and excruciating detail about some of the manufacturing processes of the author's time.)