Starch is also applied by a similar machine. The cloth is dipped into a body of starch, or the same is applied by hand, and then the superfluous starch squeezed out as the clothes are passed through the rollers. But for hotels and other large institutions washing is now done by steam-power machinery. It is an attractive sight to step into a modern laundry, operated with the latest machinery on the largest scale. The first thing necessary in many localities is to clarify the water. This is done by attaching to the service pipe tanks filled with filtering material, through which the water flows before reaching the boiler. The driving engine and shafting are compactly placed at one end or side of the room, with boilers and kettles conveniently adjacent. The water and clothes are supplied to the washing-machine, and operated by the engine. Steam may be used in addition to the engine to keep it boiling hot, or steam may be substituted entirely for the water. The machine may be one of several types selected especially for the particular class of goods to be washed. There is the dash-wheel, constructed on the principle of the cylinder churn; the outer case being stationary and the revolving dash-wheel water-tight, or perforated, which is the preferred form for collars and cuffs. In place of the dash-wheel cylinders are sometimes used, having from sixty to seventy revolutions a minute. Another form has vibrating arms or beaters, giving between four hundred and five hundred strokes a minute, and by which the clothes are squeezed between rubbing corrugated boards. The rubbing boards also roll the clothes over and over until they are thoroughly washed. In another form a rotating cylinder for the clothes is provided with an arrangement of pipes by which either steam, water or blueing can be introduced as desired, into the cylinder, through its hollow journals, so that the clothes can be washed, rinsed, and blued without removal from the machine. Another type has perforated, reciprocating pistons, between which the clothes are alternately squeezed and released, a supply of fresh water being constantly introduced through one of the hollow cylinder journals, while the used water is discharged through the opposite journal; and in still another the clothes are placed in a perforated cylinder within an outer casing, and propeller blades, assisted by other spiral blades, force a continuous current of water through the clothes. In ironing, hollow polishing rolls of various sizes are used, heated either by steam or gas. The articles to be ironed are placed in proper position upon a table and carried under and in contact with the rolls. Or the goods are ironed between a heated cylinder and a revolving drum covered with felting, and the polishing effected by the cylinder revolving faster than the drum. Ingenious forms of hand-operated ironing machines for turning over and ironing the edges of collars, and other articles, are in successful use. CHAPTER XXI.