“The Witchery of Sleep” records for us some interesting mechanical devices for inducing sleep, more common in Europe than in this country. Their inventors hope to perfect them so that they may take the place of drugs and “sleeping potions.” This is an end devoutly to be wished by all who know the steady increase of the “drug habit.” Among these sleep-inducing instruments the newest is the “vibrating coronet.” This coronet has three metal bands which encircle the head and two strips extending to the eyelids. By means of a spring these strips vibrate the eyelid gently and induce drowsiness. All the mechanical devices are constructed on the plan of inducing eye-weariness, whether by vibration or by fixity. Either effect is in accordance with the modern theories of sleep. Sleep may be induced by monotony also of sounds; by concentration either of the attention or the hearing on one point, or by more numerous impressions than the eye can comfortably receive; thus, when riding in a train, the succession of views will often induce sleepiness. The “Alouette,” a collection of little mirrors attached to the ebony panels of a box, is so placed that a ray of light falls on the mirrors in such a way as to fatigue the eye of the beholder. Both this and the “Fascinator,” a highly polished nickel ball attached to a flexible wire depending from a metal band similar to the “Coronet,” work on the plan of concentrating the vision. In a similar way a light-house or a miniature flashlight, with its appearing and disappearing light, induces drowsiness, possibly hypnotic, through incessant change. It is needless to say that these devices might be injurious to the sight and certainly would not work where the cause of sleeplessness is eyestrain. That is a case for the oculist. But when it is impossible to obtain mechanical devices, there are many simple schemes of inducing sleep. Any light work, mental or physical, is helpful. To start writing letters, particularly if one is not fond of letter-writing, will sometimes induce sleepiness very quickly. Sorting and arranging old papers will have the same effect, unless one is of a nature to find such an occupation exciting. Of course, a drawback in any of these light occupations is that by the time one has undressed drowsiness may have fled. That possibility makes it desirable that all preparations for bed shall first be made and a warm robe with comfortable bedroom shoes shall constitute the only extra clothing. Warmth of body, especially of the feet, is essential to sleep. Sometimes so simple a thing as a hot-water bottle at the feet, or even woolen bed-socks, will make all the difference between wakefulness and refreshing slumber.