The chemical and calorific determinations of coals purchased for the use of the Government have resulted in the delivery of a better grade of fuel without corresponding increase in cost, and, consequently, in saving to the Government. Under this system, of purchasing its coal under specifications and testing, the Government is getting more nearly what it pays for and is paying for what it gets. These investigations, by suggesting changes in equipment and methods, are also indicating the practicability of the purchase of cheaper fuels, such as bituminous coal and the smaller sizes of pea, buckwheat, etc., instead of the more expensive sizes of anthracite, with a corresponding saving in cost. The Government’s fuel bill now aggregates about $10,000,000 yearly. [Illustration: PLATE XXII. Fig. 1.--Dryer for Lignite Briquetting Press. Fig. 2.--Lignite Briquetting Machine.] The making and assembling of chemical analyses and calorific determinations (checked by other tests) of carefully selected samples of coals from nearly 1,000 different localities, in the different coal fields of the United States, with the additions, from time to time, of samples representing parts of coal fields or newly opened beds of coal in the same field, furnish invaluable sources of accurate information, not only for use of the Government, but also for the general public. Of the above-mentioned localities, 501 were in the public-land States and 427 in the Central, Eastern, and Southern States. The chemical analyses of the coals found throughout the United States have been made with such uniformity of method, both as to collection of samples and analytical procedure, as to yield results strictly comparable for coals from all parts of the country, and furnish complete information, as a basis for future purchases and use by the Government and by the general public, of all types of American coals. Other researches have resulted in the acquirement of valuable information regarding the distribution of temperature in the fuel bed of gas producers and furnaces, showing a range of from 400° to 1,300° cent., and have thus furnished data indicating specific difficulties to be overcome in gas-producer improvements for greater fuel efficiency. The recent studies of the volatile matter in coal, and its relation to the operation of coke ovens and other forms of combustion, have demonstrated that as much as one-third of this matter is inert and non-combustible, a fact which may have a direct bearing on smoke prevention by explaining its cause and indicating means for its abatement. Experiments in the storage of coal have proven that oxygen is absorbed during exposure to air, thereby causing, in some cases, a deterioration in heating value, and indicating that, for certain coals, in case they are to be stored a long time for naval and other purposes, storage under water is advisable.