Berkeley,
George (1685-1753):
Irish philosopher. Became Bishop of Cloyne in 1734.
"It is evident to anyone who takes a survey of the objects of human knowledge, that they are either ideas actually (1) imprinted on the senses, or else such as are (2) perceived by attending to the passions and operations of the mind, or lastly, ideas (3) formed by help of memory and imagination, either compounding, dividing or barely representing those originally perceived in the aforesaid ways....
...Thus, for example, a certain colour, taste, smell, figure and consistence having been observed to go together, are accounted one distinct thing, signified by the name apple".
Treatise Concerning the Principles of Human Knowledge. George Berkeley. (1710). Part one.
Russell, Bertrand Arthur William (1872-1970): British philosopher who studied mathematics and philosophy at Trinity College, Cambridge.
"Let us give the name of 'sense data' to the things that are immediately known in sensation: such things as colours, sounds, smells, hardnesses, roughnesses, and so on. We shall give the name 'sensation' to the experience of being immediately aware of these things. Thus, whenever we see a colour, we have a sensation of the colour, but the colour itself is a sense-datum, not a sensation. The colour is that of which we are immediately aware, and the awareness itself is the sensation."
The Problems Of Philosophy. Bertrand Russell. Paperback edition. (Oxford University Press 1967). Page four.