Another cause of their delusion was too great a dependence upon the imagination.  We shall find no lesson more clearly taught by history, by experience, or by observation, than this, that man is never safe while either his fancy or his feeling is the guiding principle of his nature.  There is a strong and constant attraction between his imagination and his passions; and, if either is permitted to exercise unlimited sway, the other will most certainly be drawn into co-operation with it, and, when they are allowed to act without restraint upon each other and with each other, they lead to the derangement and convulsion of his whole system.  They constitute the combustible elements of our being:  one serves as the spark to explode the other.  Reason, enlightened by revelation and guided by conscience, is the great conservative principle:  while that exercises the sovereign power over the fancy and the passions, we are safe; if it is dethroned, no limit can be assigned to the ruin that may follow.  In the scenes we have now been called to witness, we have perceived to what lengths of folly, cruelty, and crime even good men have been carried, who relinquished the aid, rejected the counsels, and abandoned the guidance of their reason.

Another influence that operated to produce the catastrophe in 1692 was the power of contagious sympathy.  Every wise man and good citizen ought to be aware of the existence and operation of this power.  There seems indeed to be a constitutional, original, sympathy in our nature.  When men act in a crowd, their heartstrings are prone to vibrate in unison.  Whatever chord of passion is struck in one breast, the same will ring forth its wild note through the whole mass.  This principle shows itself particularly in seasons of excitement, and its power rises in proportion to the ardor and zeal of those upon whom it acts.  It is for every one who desires to be preserved from the excesses of popular feeling, and to prevent the community to which he belongs from plunging into riotous and blind commotions, to keep his own judgment and emotions as free as possible from a power that seizes all it can reach, draws them into its current, and sweeps them round and round like the Maelstrom, until they are overwhelmed and buried in its devouring vortex.  When others are heated, the only wisdom is to determine to keep cool; whenever a people or an individual is rushing headlong, it is the duty of patriotism and of friendship to check the motion.

In this connection it may be remarked—­and I should be sorry to bring the subject to a close without urging the thought upon your attention—­that the mere power of sympathy, the momentum with which men act in a crowd, is itself capable of convulsing society and overthrowing all its safeguards, without the aid or supposed agency of supernatural beings.  The early history of the colony of New York presents a case in point.