Hume speaks of "perceptions of the mind" several times in paragraphs 1 through 3. [text] While he does not offer a definition of "perception of the mind" he gives several examples in those paragraphs and the examples include pains, pleasures, anticipations of the imagination, [text] feeling anger, and thinking of anger [text]. The phrase "of which we are conscious" appears in paragraph 3. [text]
[text] Notice Hume draws the distinction between impressions and ideas in terms of their differing degrees of "liveliness."
Hume first uses this term (in the Enquiry) in paragraph 6. [text]
Hume distinguishes outward and inward sentiment in paragraph 5. His claim, there that "all the materials of thinking are derived either from our outward or inward sentiment . . . Or, to express myself in philosophical language, all our ideas . . . are copies of our impressions . . .," [text] shows that he is using "sentiment" as a synonym for "impression."
That Hume considers anger to be an impression (or sentiment) is clear from the point (and context) of his example in the second sentence of paragraph 2: "A man in a fit of anger . . ." [text]
[text] But Hume admits (indeed, insists) that the term "innate idea"is not clear.