Read this excerpt from Charles Mackay’s book Memoirs of Extraordinary Popular Delusions and the Madness of Crowds, published in 1852, in which the author shares his perspective on money schemes that had fooled many people. Consider what analogies, or comparison, Mackay makes in this passage.

Money, again, has often been a cause of the delusion of multitudes. Sober nations have all at once become desperate gamblers, and risked almost their existence upon the turn of a piece of paper. To trace the history of the most prominent of these delusions is the object of the present pages. Men, it has been well said, think in herds; it will be seen that they go mad in herds, while they only recover their senses slowly, and one by one.