FLUNITUUE rOR COTTAGP: DWELLINGS. 33J 6G6. Air Beds and Cunliions wore inveiited by John Clark of Bridgewater, in 1813. He first renders the case of the bed, pillow, hammock, or cushion, impervious to air, by preparing it with caoutchouc; he next encloses it in another case not impervious to air, and afterwards forces the air into the inner case by means of an air-pump, j)reventing it from returning by an air-tiglit stopcock. He observes " that these beds aflbrd the most renovating and easy repose ; that they may be rendered soft to any required degree, and either cool or warm, by changing the air j that, on tlie general principle of fluids main- taining a uniform level, they are not subject to hard lumps or knots, like feathers, wool, or down ; that they never can get damp ; that they require no making up ; that the largest bed weighs only a few ounces, and that, being exhausted, they may be folded or rolled up, so as to go in very little bulk, and hence their great advantage to travellers." For medical purposes, he says, " they may be filled with air at any required temperature; or witii water, steam, or other fluids, either wet or dry, elastic or non-elastic, to which the case is impermeable. Seamen's hammocks, if filled with air, would be light, portable, and buoyant ; and, in case of ship«Teck, might be used as life preservers. Cushions, pads, and carriage linings thus, filled, will also be eligible and commodious, from their lightness and elasticity. {Repertory of Arts, vol. xxiv. p. 157.) 667. The Hi/drostatic Bed for Invctlids is a recent invention of that enlightened and benevolent physician Dr. Arnott, the author of the Elements of Physics, and is already coming into general use in the London hospitals. Its object is to mitigate all, and entirely to prevent some, of the evils attendant on remaining for a great length of time in a reclining posture. " The health, and even life, of every part of the animal body depends on the sufficient circulation through it of fresh blood, driven in by the force of the heart. Now, when a man is sitting or lying, the parts of his flesh compressed by the weight of his body do not receive the blood so readily as at other times ; and if, iVom any cause, the action of liis heart has become weak, the interruption of the circulation will both follow more quickly and be more complete. A peculiar uneasiness arises where the circulation is thus obstructed, impelling even ahealthy person to involuntary changes of position : when the body is debilitated with sickness, however, these changes occasion much fatigue ; and should the sensations after a time become indistinct, as in deUrium, palsy, &c., or the patient have become too weak to obey them, the compressed parts are kept so long without their natural supply of blood, that they lose their vitality, and change to what are called sloughs, or mortified parts. These have afterwards to be thrown oW, if the patient survive, by the process of ulceration ; and they leave deep holes, which require to be filled up with new flesh during a tedious convalescence. Many a fever, after a favourable crisis, has terminated fatally from this cause ; and the same termination is common in lingering consumptions, palsies, spine diseases, &c. ; and, generally, in all diseases which confine patients long to their beds." {Penny Mag., vol. i. p. 215.) Dr. Arnott, having tried various descriptions of beds contrived for invalids, including air pillows, down pillows, &c., thought at last of a hydrostatic bed. He " reflected that the support of water to a floating body is so uniformly diffused, that every thousandth part of an inch of it has, as it were, its own separate liquid pillar, and no one part bears the load of its neighbour ; that a person resting in a bath is nearly thus sup- ported ; that a patient nught be laid upon the surface of a bath over which a large sheet of waterproof India rubber cloth had been previously thrown, his body being rendered sufficiently buoyant by a soft mattress being placed beneath it ; and that it might thus repose upon the surface of the water, without sensible pressure any where." {Ibid.) The hydrostatic bed is made of the usual dimensions ; and is nothing more than & wooden trough, say four feet wide, six feet long, and one foot deep, lined with lead or zinc, to render it water-tight. Over this is thrown a sheet of India rubber cloth, as large as would be a complete lining to the box if it were emptj'. The edges of this sheet are secured by narrow slips of wood, or tinned iron hooping, firmly screwed down all round the top of the trough, shutting in the water as completely as if it were in a bottle, the only opening being at one end, which is filled by a cock. Upon this India rubber sheet a mattress, pillow, and bedclothes are laid, as in common beds. The box may be made by any carpenter, and lined by any plumber, and the India- rubber cloth is manufactured by Mackintosh and Co., Charing Cross. 668. Bed Furniture. The usual material for the hangings of cottage beds, especially for tent beds, is dimity, which has the advantage of being easily washed, and may thus be always contrived to have a clean appearance. Printed cottons, Manchester stripes, and chintzes are also very suitable, particulaily the latter, for French beds ; but moreens and other woollen stuflTs should never be used in cottages, as they have not only too heavy an appearance for a small room, but are liable to harbour dust and vermin. The furniture of the bed, and the curtains of the windows of the room in which it is placed, should always be of the same material and colour. 669. Window Curtains give such an air of comfort to a room, whether it be to the
