Full Idea
We use the external senses ...to make us know their particular objects ...but they do not make us know what those sensible qualities are ...whether red is small revolving globules causing light, heat a whirling of dust, or sound is waves in air.
Gist of Idea
We know objects by perceptions, but their qualities don't reveal what it is we are perceiving
Source
Gottfried Leibniz (Letters to Queen Charlotte [1702], 1702)
Book Reference
Leibniz,Gottfried: 'Leibniz Selections', ed/tr. Wiener,Philip P. [Scribners 1951], p.355
A Reaction
These seems to be exactly the concept of secondary qualities which Locke was promoting. They are unreliable information about the objects we perceive. Primary qualities are reliable information. I like that distinction.