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DIRECT-ACTORS.
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are therefore, taken along with their driving organs, com- plete machines.
This is equally true of pumps (which are only place-changing machines), of looms, shaping-machines, sawing-machines (which are both form and place-changing machines), and so on ; in short, for all machines arranged so as to be driven by a prime-mover,
FIG. 357.
FIG. 358.
whatever the nature of the latter be. Such machines we may call collectively direct- actors. By practical machine-makers they have long been considered complete machines, in opposition to the conceptions of the theorists, so that here again we find the popular view to be fully justified upon strictly theoretical grounds.
