This book is intended to be a presentation of the physical principles and mechanism employed in the equipment that has been developed for domestic convenience. Its aim is to provide information relative to the general practice of domestic engineering. The scope of the work is such as to present: first, the use of household mechanical appliances; second, the principles involved and the mechanism employed. It is not exhaustive, neither does it touch many of the secondary topics that might be discussed in connection with the various subjects. It does, however, describe at least one representative piece of each type of household apparatus that is used in good practice.

The mechanism used in the equipment of a modern dwelling is worthy of greater attention, as a course of study, than it has been heretofore accorded. The fact that any house, rural or urban, may be provided with all domestic conveniences included in: furnace heating, mechanical temperature regulation, lighting facilities, water supply, sewage disposal and other appliances, indicates the general use of domestic machinery in great variety. To comprehend the application and adaptability of this mechanism requires a knowledge of its general plan of construction and principles of operation.

Heating systems in great variety utilize steam, hot water, or hot air as the vehicle of transfer of heat from the furnace, throughout the house. Each of these is made in the form of special heating plants that may be adapted, in some special advantage to the various conditions of use. A knowledge of their working principles and general mechanical arrangement furnishes a fund of information that is of every day application.

The systems available for household water distribution take advantage of natural laws, which aided by suitable mechanical devices and conveniently arranged systems of pipes, provide water-supply plants to satisfy any condition of service. They may be of simple form, to suit a cottage, or elaborated to the requirements of large residences and made entirely automatic in action. In each, the apparatus consists of parts that perform definite functions. The parts may be obtained from different makers and assembled as a working unit or the plant may be purchased complete as some special system of water supply. An acquaintance with domestic water supply apparatus may be of service in every condition of life.

The type of illumination for a house or a group of buildings, may be selected from a variety of lighting systems. In rural homes, choice may be made between oil gas, gasolene, acetylene and electricity, each of which is used in a number of successful plants that differ only in the mechanism employed.

Any building arranged with toilet, kitchen and laundry conveniences must be provided with some form of sewage disposal. Private disposal plants are made to meet many conditions of service. The mechanical construction and principles of operation are not difficult to comprehend and their adaptation to a given service is only an intelligent conception of the possible conditions of disposal, dependent on the natural surroundings.

There are few communities where household equipment cannot be found to illustrate each of the subjects discussed. Most modern school houses are equipped for automatic control of temperature, ventilation and humidity. They are further provided with systems of gas, water and electric distribution and arrangements for sewage disposal. These facilities furnish demonstration apparatus that are also examples of their application. Additional examples of the various forms of plumbing and pipe fittings, valves, traps and water fixtures may be found in the shop of dealers in plumbers and steam-fitters supplies.

Attention is called to the value of observing houses in process of construction and the means employed for the placement of the pipes for the sewer, gas, water, electric conduits, etc. These are generally located by direction of the specifications provided by the architect but observation of their installation is necessary for a comprehension of actual working conditions. It is suggested that the work be made that of, first, acquiring an idea of established practice, and second, that of investigating the examples of its application.