Reed water tube boiler straight tubes through which water and steam circulated more freely, it was considered by some contemporary writers on the subject such as Leslie S. Robertson as "behind" in its circulation because of the absence of down-comers. Whereas the Yarrow boilers fitted to the armoured cruiser of 1905 evaporated 11.664 pounds (5.291 kg) of water per pound (454 g) of coal at 100 degrees centigrade (212 degrees Fahrenheit) with natural draught, by the same measure a Reed boiler as fitted to the torpedo boat destroyer of 1896 evaporated 12 pounds (5.44 kg). An advantage of the Yarrow boiler was in weight:
Water quality how the water will be used. In the case of natural water bodies, they also make some reasonable estimate of pristine conditions. Natural water bodies will vary in response to environmental conditions. Environmental scientists work to understand how these systems function, which in turn helps to identify the sources and fates of contaminants. Environmental lawyers and policymakers work to define legislation with the intention that water is maintained at an appropriate quality for its identified use. The vast majority of surface water on the Earth is neither potable nor toxic. This remains true when seawater in the oceans (which is