So much has been written and said about the arrangement, design, and working of the baths of the ancient Romans, and of the Oriental nations of to-day, that it will be superfluous and unnecessary here to enter upon the subject, fascinating though it be to any one interested in the building of modern baths. An intelligent study of old plans, and of the writings of those who have given their attention to the elucidation of the special purposes to which the various apartments of the Roman _Thermæ_ were devoted, serves in no small degree to a complete understanding of the problems involved in the perfecting of the bath in modern times. So also with regard to the Hammam of the East, an acquaintance with its plan and working is equally instructive. But to fully elucidate the history of thermo-therapeutic architecture would require a volume of itself, since the many questions that present themselves to the student of ancient baths cannot be properly understood without considerable and lengthy description. Those desirous of studying the subject of the design of ancient and Oriental baths will find many works within easy reach. In his 'Manual of the Turkish Bath,' the late David Urquhart has given a most complete account of Eastern baths; and in Sir Erasmus Wilson's 'Eastern or Turkish Bath,' will be found a popular account of the sumptuous baths of antiquity, which will serve as an introduction to further researches with the aid of more abstruse works, such as Wollaston's 'Thermæ Romano-Britannicæ,' Cameron's 'Baths of the Romans,' and particularly the careful description of the Pompeian _Balneæ_ in Sir William Gell's 'Pompeiana.' In the admirable works of Samuel Lysons, the Gloucestershire antiquary, will be found interesting accounts of the remains of old Roman baths in this country; and in Daremberg and Saglio's 'Dictionnaire des Antiquités Grecques et Romaines,' is a most capable essay on ancient _Balneæ_. In Eastern travellers' books, desultory descriptions of the Oriental bath will be found; and in Owen Jones's work on the Palace of the Alhambra, at Granada, plans and sections are given of the elegant little bath that the Moorish builders erected therein. For the purposes of this work, and for the sake of brevity and convenience, I have thought fit to adopt the following terms from the old Roman vocabulary, to designate the apartments of the modern bath. I respectively term the first, second, and third hot rooms, the _Tepidarium_, _Calidarium_, and _Laconicum_. Although the exact nature of the ancient Roman _laconicum_ is still a question in debate, I have chosen to employ the term to designate herein the hottest of the hot. The washing room I call the _Lavatorium_; the cooling room, the _Frigidarium_; and the separate dressing room, the _Apodyterium_.