By a vote passed in March, 1817, the Senate had required of Mr. Adams a report on weights and measures; and in December, 1819, the House of Representatives had by a resolution made the same requisition. To this subject he had directed his attention when in Russia; and had devoted the leisure his duties as Secretary of State permitted, without approximating to its completion, owing to the number and perplexity of details its pursuit involved. In the summer of 1820 he relinquished a visit to his father and friends in Massachusetts, and concentrated his attention, during six months, exclusively on this report, which he finished and made to Congress, in February, 1821. At the conclusion of his work he thus expresses himself: "This subject has occupied, for the last sixty years, many of the ablest men in Europe, and to it all the powers, and all the philosophical and mathematical learning and ingenuity, of France and Great Britain, have been incessantly directed. It was a fearful and oppressive task. It has been executed, and it will be for the public judgment to pass upon it." From the abstruse character of this work, the labor, research, and talent, it evidences have never been generally and justly appreciated. It commences with the wants of individuals antecedent to the existence of communities, and deduces from man's physical organization, and from the exigences of domestic society, the origin of _measures of surface, distance, and capacity_; and that of _weight_, from the difference between the specific gravity of substances and its importance in the exchange of traffic consequent on the multiplication of human wants, with the increase of the social relations. He then proceeds to state and analyze the powers and duties of legislators on the subject, with their respective limitations. The results of his researches relative to the weights and measures of the Egyptians, Hebrews, Greeks, and Romans, are successively stated. From the institutions of the nations of antiquity he derives those of modern Europe and of the United States. He praises the "stupendous and untiring perseverance of England and France" in this field, and explains the causes which have not rendered their success adequate to their endeavors. The system of modern France on this subject he investigates and applauds, as "one of those attempts to improve the condition of human kind, which, although it may ultimately fail, deserves admiration, as approaching more nearly than any other to the ideal perfection of uniformity in weights and measures." After stating the difficulties which prevented other nations from seconding the endeavors of France, Mr. Adams concludes this elaborate treatise with the opinion that universal uniformity on the subject can only be effected by a general convention, to which all the nations of the world should be parties. Until such a general course of measures be adopted, he regards it as inexpedient for the United States