Though specific plans can not be sent in the absence of definite information, and though plans and specifications can not be prepared to meet individual requirements, the Division of Agricultural Engineering, Bureau of Public Roads, gladly gives such help as is possible. To those who contemplate installing sewerage works on farms and who furnish the information outlined under the caption "Field data," on page 52, plans, advice, or suggestions will be sent. Local requirements are frequently met or approximated by one of the designs on hand; working drawings in the form of blue prints will then be furnished. Sometimes the designs, slightly modified, may suit the needs. In other instances it is sufficient to send published bulletins or give written suggestions of a practical nature. SEWAGE, SEWERS, AND SEWERAGE DEFINED. Human excrements (feces and urine) as found in closets and privy vaults are known as night soil. These wastes may be flushed away with running water, and there may be added the discharges from washbasins, bathtubs, kitchen and slop sinks, laundry trays, washing vats, and floor drains. This refuse liquid product is sewage, and the underground pipe which conveys it is a sewer. Since sewers carry foul matter they should be water-tight, and this feature of their construction distinguishes them from drains removing relatively pure surface or ground water. Sewerage refers to a system of sewers, including the pipes, tanks, disposal works, and appurtenances. NATURE AND QUANTITY OF SEWAGE. Under average conditions a man discharges daily about 3-1/2 ounces of moist feces and 40 ounces of urine, the total in a year approximating 992 pounds.[1] Feces consist largely of water and undigested or partially digested food; by weight it is 77.2 per cent water. 2 Urine is about 96.3 per cent water.[2] [1] Practical Physiological Chemistry, by Philip B. Hawk, 1916, pp. 221, 359. [2] Agriculture, by F. H. Storer, 1894, vol. 2, p. 70. The excrements constitute but a small part of ordinary sewage. In addition to the excrements and the daily water consumption of perhaps 40 gallons per person are many substances entering into the economy of the household, such as grease, fats, milk, bits of food, meat, fruit, and vegetables, tea and coffee grounds, paper, etc. This complex product contains mineral, vegetable, and animal substances, both dissolved and undissolved. It contains dead organic matter and living organisms in the form of exceedingly minute vegetative cells (bacteria) and animal cells (protozoa). These low forms of life are the active agents in destroying dead organic matter.