The sources of exhaust steam, engines or pumps, are operating usually twenty-four hours daily and constantly pouring steam into the exhaust mains, which is constantly radiating, leaking and the accumulated moisture is being trapped away to a sewer or feed water heater. The traps are usually just a little out of order, and the little leaks in multiple mount up fast. Again the apparatus in almost any department used for cooking and manufacturing is irregular in its use and an actual record will show hardly to exceed six hours’ demand or use. Why operate engines and pumps at a disadvantage all the time for the sake of a supply six or eight hours daily? The engine and pump requirement increases rapidly with the exhaust steam pressure and requires larger production from the boiler. Any power like that needed for pumping can be transmitted on a wire with far less loss than as steam through a pipe. The recommendations then are: Produce electricity as cheaply as possible; if electricity is made, use high class equipment operating condensing and take advantage of superheat if possible; produce refrigeration or compress air with the same intelligence; perform all pumping with electrically operated pumps; distribute steam for all uses at high pressure, at high velocity through small pipes, well insulated and have the heat at the process when needed; fit boilers so they can arise to a demand when needed with ample stack and draft; install stokers, if the plant will justify it; insulate the boiler walls and generate steam as cheaply as possible--and don’t waste it. =Boilers.=--The common types of boilers in the United States are the fire tube boiler and the water tube boiler. The first named kind is that which suggests itself to the reader when a boiler is mentioned and consists of a shell cylindrical in form with a head in each end into which tubes are expanded. In operation the water surrounds the tubes and the fire passes through them. The water tube boiler is the opposite of this. There are variations of these and boilers that are built using both principles in part. There are also Cornish, Lancashire and Yorkshire types used in England which are fire tubes using only one or two tubes. Where a plant requirement is up to 500 horsepower, the fire tube is the usual installation owing to its cheaper cost, and more units which enables more continuous operation, especially if a unit is out of service for cleaning, 100, 125 or 150 horse-power being the standard size units. If a plant requires 750 horse-power or more, installation of the water tube is preferable owing to their requiring less floor space, higher pressures are usually carried and they are regarded as more safe under these conditions. They can be forced to a higher output if demanded, which is an advantage in times of rush business.