man, dressed in a snuff-colored coat, stepped forward, and, drawing a pistol from an inside pocket fired at and shot the small man, the bullet lodging in the left breast.  In the vision, Williams turned and asked some bystander the name of the victim; the bystander replied that the stricken man was Mr. Spencer Perceval, the Chancellor of the Exchequer.  The valuable feature of the case, from a scientific standpoint, lies in the fact that Williams was very much impressed by his thrice-repeated vision, and was greatly disturbed thereby.  His anxiety was so great that he spoke of the matter to several friends, and asked them whether it would not be well for him to go to London for the purpose of warning Mr. Perceval.  His friends ridiculed the whole matter, and persuaded him to give up the idea of visiting London for the purpose named.  Those who had a knowledge of the vision were greatly startled and shocked when several days afterward the assassination occurred, agreeing in perfect detail with the vision of the Cornishman.  The case, vouched for as it was by a number of reliable persons who had been consulted by Williams, attracted much attention at the time, and has since passed into the history of remarkable instances of prevision.

In some cases, however, the prevision seems to come as a warning, and in many cases the heeding of the warning has prevented the unpleasant features from materializing as seen in the vision.  Up to the point of the action upon the warning the occurrence agree perfectly with the vision—­but the moment the warned person acts so as to prevent the occurrence, the whole train of circumstances is broken.  There is an occult explanation of this, but it is too technical to mention at this place.

What is known to psychic researchers as “the Hannah Green case” is of this character.  This story, briefly, is that Hannah Green, a housekeeper of Oxfordshire, dreamt that she, having been left alone in the house of a Sunday evening, heard a knock at the door.  Opening the door she found a tramp who tried to force his way into the house.  She struggled to prevent his entrance, but he struck her with a bludgeon and rendered her insensible, whereupon he entered the house and robbed it.  She related the vision to her friends, but, as nothing happened for some time, the matter almost passed from her mind.  But, some seven years afterward, she was left in charge of the house on a certain Sunday evening; during the evening she was startled by a sudden knock at the door, and her former vision was recalled to her memory quite vividly.  She refused to go to the door, remembering the warning, but instead went up to a landing on the stair and looked out the window, she saw at the door the very tramp whom she had seen in the vision some seven years before, armed with a bludgeon and striving to force an entrance into the house.  She took steps to frighten away the rascal, and she was saved from the unpleasant conclusion of her vision.  Many similar cases are recorded.