Date: 1779-1780, 1781

"These clouds which he perceived gathering on his intellects he endeavoured to disperse by travel, and passed into France; but found himself constrained to yield to his malady, and returned."

— Johnson, Samuel (1709-1784)

Date: 1779, 1781

"The variable weather of the mind, the flying vapours of incipient madness, which from time to time cloud reason, without eclipsing it, it requires so much nicety to exhibit, that Addison seems to have been deterred from prosecuting his own design."

— Johnson, Samuel (1709-1784)

Date: 1783

The human body is like a barometer: "If the external air can affect the motions of so heavy a substance as mercury, in the tube of the barometer; we need no wonder, that it should affect those finer fluids, that circulate through the human body."

— Beattie, James (1735-1803)