A lady of what is commonly called an uncertain temper -- a phrase which being interpreted signifies a temper tolerably certain to make everybody more or less uncomfortable.
Source: Of Martha Varden, in Barnaby Rudge, ch. 7, 1841.
-- Charles Dickens, (Feb 7 1812-1870), English novelist, dramatist; He was one of most prolific and popular English novelists, e.g., A Christmas Carol, 1843 & Tale of Two Cities, 1859.