From Introduction Scope and Purpose of Inquiry: "The Bureau of Mines, to which the testing and analyzing of fuels as carried on by the United States Geographical Survey has been transferred, is continuing producer-gas investigations at the testing station at Pittsburgh, Pa. Results of the gas-producer tests made at the coal-testing plant erected at St.Louis, Mo., and of a study of some of the problems that came up in the tests have been published by Geological Survey. Results of the tests made at Norfolk, Va., and Pittsburgh, Pa. and of further studies of particular problems, will be published by the Bureau of Mines."

From Scope of Report: "The purpose of this report is, therefore, to present in convenient form all the more important data accumulated in the course of the tests described, in order that the results may be readily accessible both to the Government officials having charge of the design, purchase, or care of power plants and to all persons interested in the development of the internal-combustion engine and the gas producer as means for utilizing the energy of fuels."

From Introduction: "The following report is a summary of the commercial results which were obtained from 2,000 tests conducted by technologic branch of the United States Geological Survey at St. Louis, Mo., and Norfolk, Va., in 1907 and 1908, under the technical supervision of R.H. Fernald, engineer in charge of the producer-gas section."

From Introduction: "With the particular equipment used in the tests both coal and briquets were far from smokeless; consequently the data of this bulletin are applicable only by analogy to parallel operation with a coal more nearly smokeless, but nevertheless applicable with much reliability. It was the original intention to make a set of preliminary steaming tests alongside a dock (which tests furnish material for this bulletin) an to finish with a set of running tests at sea; but the running tests were never made. for lack of time and men."

From Object of Tests: "The primary object of the tests was to study the relative performances of the two types of briquets and of the coal, with reference to efficiency, tendency to smoke, and the ease with which steam could be kept up, when each of the three varieties of fuel was burned at several rates of combustion. Many secondary objects were in mind, the data concerning which are discussed under "Effect of varying rates of combustion," pages 20-27."

From Introduction: "For purpose of procuring data that could be using in estimating the value of the briquetting process as applied to American fuels, the United States Geological Survey, in cooperation with other interests, began in 1904, at the Louisiana Purchase Exposition, certain experiments involving the production and use of bituminous-coal briquets."

From Introduction: "Perhaps the most important result obtained is that showing the relative value of different fuels for domestic purposes. From Table 16. on page 39, it is possible by comparison to arrive at the probable value of any fuel in any part of the country. The figures in the table show that with a sectional boiler the effectiveness of different fuels depends on the number of thermal units they contain. A brief summary of the results of this investigation is given on page 41."

From Introduction: "This report therefore covers all such work up to its completion in July, 1906. In the following pages the results of each line of experimental work are given under a special heading indicating the object of the investigation."

From Introduction: "In the course of this study many incidental problems of prime importance have demanded consideration. Among them is the determination, under practically constant conditions, of the duration of gas-producer tests necessary to reduce the possible error to minimum. A discussion of this proper length of test period forms the part of this bulletin."

From Introduction: "The problem is always to produce at a profit a briquet of satisfactory grade for the use intended. This problem will be made clearer by a brief summary of the available binders, followed by a preliminary discussion of the characteristics of a good briquet."