a time lag between the time a slave is captured and the time he or she is sold. Thus there would often have been a pool of slaves awaiting sale, who would have been put to work. There are possible additional reasons for the adoption of slavery by the locals to meet their labour requirements: The Europeans provided an example for imitation. Once slaving in any form is accepted, it may smash a moral barrier to exploitation and make its adoption in other forms seem a relatively minor matter. Export slaving entailed the construction of a coercive apparatus which could have been subsequently turned to other ends, such as policing a captive labour force. The sale of local produce (e.g., palm kernels) to Europeans opened a new sphere of economic activity. In particular, it created an increased demand for agricultural labour. Slavery was a way of mobilising an agricultural work force. This local African slavery was much less harsh and brutal than the slavery practiced by Europeans on, for example, the plantations of the United States, the West Indies, and Brazil. The local slavery has been described by anthropologist M. McCulloch: Slaves were sometimes sent on errands outside the kingdoms of their masters and returned voluntarily. Speaking specifically of the era around 1700, historian Christopher Fyfe relates that, "Slaves not taken in war were usually criminals. In coastal areas, at least, it was rare for anyone to be sold without being charged with a crime." Voluntary dependence reminiscent of that described in the early Portuguese documents mentioned at the beginning of this section was still present in the 19th century. It was called pawning; Arthur Abraham describes a typical variety: Some observers consider the term "slave" to be more misleading than informative when describing the local practice. Abraham says that in most cases, "subject, servant, client, serf, pawn, dependent, or retainer" would be more accurate. Domestic slavery was abolished in Sierra Leone in 1928. McCulloch reports that at that time, amongst Sierra Leone's largest present-day ethnolinguistic group, the Mende, who then had about 560,000 people, about 15 per cent of the population (i.e., 84,000 people) were domestic slaves. He also says that "singularly little change followed the 1928 decree; a fair number of slaves returned to their original homes, but the great majority remained in the villages in which their former masters had placed them or their parents." Export slavery