Full Idea
Such qualities, which are nothing in objects but powers to produce various sensations in us by their primary qualities i.e. by the bulk, figure, texture, and motion of their sensible parts, as colours, sounds, tastes etc. These I call secondary qualities.
Gist of Idea
Secondary qualities are powers of complex primary qualities to produce sensations in us
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.08.10)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.135
A Reaction
Alexander emphasises that secondary qualities are in objects. It is the ideas (here 'sensations') which are in us. This quotation shows that secondary qualities are not identical with 'textures' (which are complex primary qualities), but are 'powers'.
Related Ideas
Idea 15973 In my view Locke's 'textures' are groups of corpuscles which are powers (rather than 'having' powers) [Locke, by Alexander,P]
Idea 15974 The essence of whiteness in a man is nothing but the power to produce the idea of whiteness [Locke]