Coates, Eric (Subject catalogues. Headings and structure. 2nd ed., 1988) – who appreciates that classification is the key to successful retrieval, even in the computer age – notes that there is a big distinction between ‘machine for washing’ in which ‘for’ signals ‘of purpose’ and ‘library for lending’ in which ‘for’ signals ‘mode of operation.’ Both can in turn be distinguished from uses of ‘of’ to denote ‘[property] of.’ It may be useful to distinguish these distinct uses, though they may be clear in context. [This will be done with respect to uses of ‘of’ as in ‘physics of metals’ where ‘applied to’ will be preferred. When ‘of’ means ‘property of’ the ‘of’ will be omitted] Note that Coates’ primary concern was citation order (of the words bracketing ‘for’), a problem much less severe if compound notation is regularly employed (and searches by each term are facilitated) . Note also that he later discusses ‘of’ uses (‘driving of piles’ and ‘wheels of bicycles’) which are best captured by causal relations or whole/part classification.