Date: 1767

"These topics will, for the most part, be very extraordinary, and altogether unexpected; but they will constantly produce the intended effect. They will operate upon the mind by surprise; they will strike like lightening, and penetrate the heart at once."

— Duff, William (1732-1815)

Date: 1774

"This activity of imagination, by which it darts with the quickness of lightning, through all possible views of the ideas which are presented, arises from the same perfection of the associating principles, which produces the other qualities of genius."

— Gerard, Alexander (1728-1795)

Date: 1776

"Whatever regards the analysis of the operations of the mind, which is quicker than lightning in all her energies, must in a great measure be abstruse and dark."

— Campbell, George (1719-1796)

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)

Date: 1783

"The utmost we can expect is, that this fire of imagination should sometimes flash upon us like lightning from heaven, and then disappear."

— Blair, Hugh (1718-1800)