Saturnine

Alſo amongſt the aforeſaid living creatures, ſome are Solar, [...] the contrary, are ſuch as are Lunar, Saturnine, and Martiall, &c. [...] The Saturnine, are the ſolitary, nocturnall and ſad: as the Aſſe, camel, cat, ape, hare, mule, mouſe, mole, bear, toad, and wolfe.

Source: wiktionary

I may cast my readers under two general divisions: the mercurial and the saturnine. The first are the gay part of my disciples, who require speculations of wit and humour; the others are those of a more solemn and sober turn, who find no pleasure but in papers of morality and sound sense.

Source: wiktionary

Theſe gentlemen, with an equal ſhare of pride, pedantry, and ſaturnine diſpoſition, were by the accidents of education and company, diametrically oppoſite in political maxims; [...]

Source: wiktionary

He [Samuel Johnson] said, "Mr. [John] Wesley's conversation is good; he talks well on any subject; I could converse with him all night." But Dr. Johnson would certainly not have expressed himself in this strong language of approbation, had Mr. Wesley been that dark, saturnine creature, represented by Archbishop [Thomas] Herring.

Source: wiktionary