Air-beds, Cushions, and Pillows.

Air-beds, Cushions, and Pillows. An inflated bladder explains the nature of these. Air-cushions, or half-beds, pillows, and travelling-cushions, differ only in shape and size. They were first made at a moderate price after the introduction of Mackintosh cloth, an air-tight fabric consisting of two pieces of cloth united by an interposed layer of india-rubber spread on in solution. They are still made in essentially the same way, a thin sheet of vulcanised rubber being placed between the two layers of cloth, and the whole made into one fabric, so to speak, by pressure. When they are inflated, either by the mouth or by a pair of bellows, a screw stop-cock prevents the escape of air. An air-bed consists of a sack in the form of a mattress, usually divided into a number of compartments, each air-tight; a projection at one end forms a bolster. Each compartment has a valve, through which the air is blown in. Air-beds and pillows are valuable in cases of sickness, but are not so lasting or so comfortable as Water-beds (q.v.) and water-pillows, which are formed of thicker material, consisting entirely of vulcanised india-rubber. The latter are, however, double the price of the former. It has been proposed to use air-beds for military purposes. If not taken good care of, they crack and become troublesome or useless. Air-beds were known as early as the beginning of the 18th century, but being made of leather, were expensive.