Boswell and Johnson held a conversation upon this experiment as follows:—Boswell. "Why, sir, do people play this trick, which I observe now when I look at your grate, putting the shovel against it to make the fire burn?"—Johnson. "They play the trick, but it does not make the fire burn. There is a better (setting the poker perpendicularly up at right angles with the grate.) In days of superstition, they thought, as it made a cross with the bars, it would drive away the witch."

Upon this, Dr. Kearney notes: "it certainly does make the fire burn: by repelling the air, it throws a blast upon the fire, and so performs the parts, in some degree, of a blower or bellows." These observations were made only as to the shovel, but the poker is equally efficacious. "After all," says Croker, "it is possible that there may be some magnetic or electrical influence, which, in the progress of science, may be explained; and what has been thought a vulgar trick, may be proved to be a philosophical experiment."

Whatever may be the cause, there is every-day evidence that a poker or shovel, as the case may be, if laid across a dull fire, will revive it; because, we think, the poker or shovel receives and concentrates the heat, and produces an additional draught through the fire.