This chapter is not intended to be a full and detailed account of anthropological field methods. Nor yet is it limited to these, but treats also of certain problems of presentation. In

either case the emphasis· will be on matters which bear closely on the nature of anthropological data and so on the mutual determination (and limitation) of technique and material. Here four points seem to stand out: ( r) the us~ of informants in anthropological observation; (2) the use of language in observation and description; (3) the effect of the observer's 'personal equation'; and (4) the extension of observation beyond tangible behavio1,1r to mental processes (the last point requiring treatment in a separate chapter).