Fuel oil pollution control and additional maintenance required after burning it often outweigh the low cost of the fuel. Burning fuel oil, particularly residual fuel oil, produces uniformly higher carbon dioxide emissions than natural gas. Heavy fuel oils continue to be used in the boiler "lighting up" facility in many coal-fired power plants. This use is approximately analogous to using kindling to start a fire. Without performing this act it is difficult to begin the large-scale combustion process. The chief drawback to residual fuel oil is its high initial viscosity, particularly in the case of No. 6 oil, which requires a correctly
The Power of Movement in Plants John Murray. This book stands at the culmination of a long line of study in plants and is immediately preceded by 'The different forms of flowers on Plants of the same species’ (1877). (See Bibliography for additional publications on plants.) These studies on plants were first evidenced in 'On the various contrivances by which British and foreign orchids are fertilised by insects’ (1862), the publication that immediately followed "On the Origin of Species By Means of Natural Selection". He co-authored this study with his son Francis Darwin (who specialised in botany) and his devotee, George Romanes, who assisted in editing