text: During the early development of boilers, water treatment was not so much of an issue, as temperatures and pressures were so low that high amounts of scale and rust would not form to such a significant extent, especially if the boiler was “blown down”. It was general practice to install zinc plates and/or alkaline chemicals to reduce corrosion within the boiler. Many tests had been performed to determine the cause (and possible protection) from corrosion in boilers using distilled water, various chemicals, and sacrificial metals. Silver nitrate can be added to feedwater samples to detect contamination by seawater. Use of lime for alkalinity control was mentioned as early as 1900, and was used by the French and British Navies until about 1935. In modern boilers, treatment of feedwater is critical, as problems result from using untreated water in extreme pressure and temperature environments. This includes lower efficiency in terms of heat transfer, overheating, damage, and costly cleaning.