All 8 Uses of

positive
in
Middlemarch

But he was positively obtrusive at this moment, and his dimpled hands were quite disagreeable.†
Chpt 1

positively = with certainty

Whatever was not problematical and suspected about this young man—for example, a certain showiness as to foreign ideas, and a disposition to unsettle what had been settled and forgotten by his elders—was positively unwelcome to a physician whose standing had been fixed thirty years before by a treatise on Meningitis, of which at least one copy marked "own" was bound in calf.
Chpt 2 *

positively = absolutely (used for emphasis)

"Positively," exclaimed Mrs. Cadwallader, "there is a new face come out from behind that broad man queerer than any of them: a little round head with bulging eyes—a sort of frog-face—do look.†
Chpt 4

positively = with certainty

And since Mary had been keeping Mr. Featherstone's house, Mrs. Vincy's want of liking for the Garths had been converted into something more positive, by alarm lest Fred should engage himself to this plain girl, whose parents "lived in such a small way."†
Chpt 3

Not for one moment did Mr. Casaubon suspect Dorothea of any doubleness: he had no suspicions of her, but he had (what was little less uncomfortable) the positive knowledge that her tendency to form opinions about her husband's conduct was accompanied with a disposition to regard Will Ladislaw favorably and be influenced by what he said.†
Chpt 4

Were I assured that this is the utmost I can reasonably expect, that assurance would be a useful circumscription of my attempts, and a guide in both the positive and negative determination of my course.†
Chpt 4

I say that there never was a meaner, more ungentlemanly action than this—a codicil of this sort to a will which he made at the time of his marriage with the knowledge and reliance of her family—a positive insult to Dorothea!†
Chpt 5

Mr. Hawley indeed, in the first instance, invited a select party, including the two physicians, with Mr Toller and Mr. Wrench, expressly to hold a close discussion as to the probabilities of Raffles's illness, reciting to them all the particulars which had been gathered from Mrs. Abel in connection with Lydgate's certificate, that the death was due to delirium tremens; and the medical gentlemen, who all stood undisturbedly on the old paths in relation to this disease, declared that they could see nothing in these particulars which could be transformed into a positive ground of suspicion.†
Chpt 7

Definitions:

(1) (positive as in: I'm absolutely positive!)
certain (having no doubt; or used for emphasis)
(2) (positive as in: had a positive effect)
good or beneficial
(3) (positive as in: positive feedback from my boss)
approval or agreement
(4) (positive as in: a positive attitude)
optimistic (expecting or focusing on good things); or agreeable
(5) (positive as in: The test came back positive.)
found a condition or substance to be present
indicating the presence of something being tested for -- especially a disease, condition, or substance
(6) (positive as in: a positive number)
greater than zero (of a number)
(7) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

See a comprehensive dictionary for less common meanings of positive including some in the fields of electricity, physics, chemistry, medicine, philosophy, and grammar. Note that most all senses of positive indicate that something is good or present.