Slavery as an industrial system

In most branches of knowledge the phenomena the man of science has to deal with have their technical names; and, when using a scientific term, he need not have regard to the meaning this term conveys in ordinary language; he knows he will not be misunderstood by his fellow-scientists. For instance, the Germans call a whale Wallfisch, and the English speak of shell-fish; but a zoölogist, using the word fish, need not fear that any competent person will think he means whales or shell-fish. In ethnology the state of things is quite different. There are a few scientific names bearing a definite meaning, such as the terms "animism" and "survival", happily introduced by Professor Tylor. But most phenomena belonging to our science have not yet been accurately investigated; so it is no wonder, that different writers (sometimes even the same writer on different pages) give different names to the same phenomenon, whereas on the other hand sometimes the same term (e.g. "matriarchy") is applied to widely different phenomena. As for the subject we are about to treat of, we shall presently see that several writers have given a definition of slavery; but no one has taken the trouble to inquire whether his definition can be of any practical use in social science. Therefore we shall try to give a good definition and justify it.