every experiment had to be noted down separately, and at full length so as to leave no room for error, a great deal of time was necessarily expended in these trials. They had, however, for result, a degree of conformity which justifies me in stating that the directions given for the quantities of spirit in the different chambers are, so far as I have been able to determine, strictly accurate; and that while the great heat is obtained by increasing the amount in the outer chamber, prolonged moderate heat is maintained by raising that in the inner chamber. The next point to get at was the requisite amount of water. Too large a volume, of course, meant an unnecessary waste of heat; on the other hand, too small a quantity exposed the bath to injury from the heat; so that a separate series of trials had to be made in order to clear up this difficulty. Finally, the height at which the bearing-ring must be fixed, so as to get the maximum of heat without the risk of putting out the flame in the inner chamber, had to be ascertained. So far as I have been able to determine, a height of an inch and a quarter to a half of its lower surface from the top of the lamp, combines all possible advantages in this direction. But something must be left to the reader's discretion. So long as the lamp burns clear and steady, and the water boils vigorously, all is right; but should the flame sink, and the slight lifting of the crinoline, as directed farther on, not revive it, the ring is most likely too low, and should be raised a quarter to half an inch. The bath is used as follows:-The bather undresses to his shirt and slippers, so as to be ready. The lid, B (fig. 4), covering the inner chamber of the lamp is to be removed. The plug, C, of the tube leading to the outer chamber is to be withdrawn. Eight drachms of good methylated spirit should be poured, by means of a measure-glass, into this chamber. The plug is then replaced. Four drachms of spirit are poured into the inner chamber. The lamp is now lighted by applying a burning match to the spirit in the inner chamber. The object of doing this at such an early stage is to secure thorough ignition of the spirit, and prevent the flame being put out when the bath is placed over it. Sometimes this process must be repeated, as the best spirit will go out now and then. In cold weather it often saves time and disappointment to warm the spirit by putting the lamp for a minute or two, after being charged, on the hob, or into a basin of hot water. Lighted paper should never be used in preference to the match. The lamp is now placed on a table, or any place where it will stand firm. The body of the bath, A A (fig. 3), is to be about half filled with hot water, which is immediately after thrown away. This is done to heat the bath. Seven ounces of hot water are again poured into the same part, thus filling it quite up to the wire ring, and the bath is carefully placed over the lamp. It is not absolutely necessary to use hot water, the heat generated by the lamp is sufficient to boil it, even when cold; but it is a great economy of time and fuel to do so, and I need scarcely say that so small a quantity can generally be procured. Unless the patient wishes, for some particular reason, to prolong the employment of the vapour, seven ounces of water will be quite sufficient. All that is requisite for ordinary purposes will be gained by converting what can be properly utilised of this quantity into steam. The bath is accordingly marked inside with a wire ring, to show how high this amount will reach. Until the patient has become quite habituated to the use of the bath, I do not advise that he should expose himself to the heat for more than ten minutes, and the amount both of the spirit and water is calculated on the basis of affording this and no more, but of affording it most effectually. Should he, however, desire to continue the use of the vapour, his object is easily carried out by adding more water, say four, five or six tablespoonfuls, and increasing the spirit in the inner chamber by two or three drachms. This, however, is one of the points which are perpetually being modified by experience. Some persons can never bear the vapour for more than a few minutes; others are so little influenced by its action that it would almost seem as if they could support it for an indefinite time. The bearing-ring of the lamp being adjusted, as before directed, to a height of an inch and a quarter, or an inch and a half, between its lower surface and the top of the lamp, the bather should wait a few moments till the flame begins to rise well up. Taking the bath by the handles, he should place it on the ring, the lowest part of it slipping through the latter (see fig. 9). Should the flame die out, he has not waited long enough, and must relight it, and replace the bath. Having satisfied himself that the lamp burns freely, he should grasp the latter firmly by the handle, and place the whole on the floor, under a chair, selecting a strong one with a cane bottom. If the floor be covered with carpet, it is scarcely requisite to insert anything between it and the lamp, but a tile is essential for this purpose if we have to deal with such substances as floor-cloth, linoleum, etc. The next step is to fold two thick Turkish towels, and place them over the seat of the chair in such a way as to cover all the openings. The fringe should be turned inwards, so that it may not catch when the bather is sitting down, or be exposed to the flame when he is placing the bath on the floor; perhaps the shortest and best way is to cut it off. After a very little practice he will easily be able to regulate this part of the process so as to allow just sufficient heat, and no more, |