[The following narrative is taken from Frederick W. True’s Semi-centennial history of the National Academy of Sciences, A History of the First Half-Century of the National Academy of Sciences 1863-1913, pp. 206-213.]
Five committees were appointed at the request of the Government within a month after the organization of the Academy. The first of these, which was known as Committee No. 1, was appointed at the solicitation of the Secretary of the Treasury, Salmon P. Chase, on May 4, 1863, not to consider any question relating to the conduct of the Civil War, but on the subject of the “Uniformity of weights, measures and coins, considered in relation to domestic and international commerce.” Secretary Chase had previously referred to this matter in his annual report for 1861, p. 28, as follows:
“The Secretary desires to avail himself of this opportunity to invite the attention of Congress to the importance of a uniform system and a uniform nomenclature of weights and measures, and coins to the commerce of the world, in which the United States already so largely shares. The wisest of our statesmen have regarded the attainment of this end, so desirable in itself, as by no means impossible. The combination of the decimal system with appropriate denominations in a scheme of weights, measures, and coins for the international uses of commerce, leaving, if need be, the separate systems of the nations untouched, is certainly not beyond the reach of the daring genius and patient endeavor which gave the steam engine and the telegraph to the service of mankind.” [Rep. Secr. Treas. for 1861, p. 28.]
The committee was originally one of eight members, namely, Joseph Henry (chairman), J. H. Alexander, Fairman Rogers, Wolcott Gibbs, Arnold Guyot, Benjamin Silliman, Jr., Wm. Chauvenet, John Torrey. To these members were added A. D. Bache, by resolution of the Academy, John Rodgers, L. M. Rutherfurd and Samuel B. Ruggles. Ruggles was not a member of the Academy, but was designated in accordance with a provision of the constitution which permitted the President “to call in the aid, upon committees, of experts, or men of remarkable attainments, not members of the Academy.” (Act 2, sect. 4.) He was the delegate of the United States to the International Statistical Congress held in Berlin in 1863.
The original committee was discharged in 1866, but the following year another committee was appointed under the same  name. It became a standing committee, and, although rated as a committee on business of the Academy, it has reported a number of times on matters referred to the Academy by the Government. During the forty-six years that have elapsed since 1867, twenty-two members of the Academy have served on this committee, including three who belonged to the original Committee No. 1. These are J. H. Alexander, F. A. P. Barnard, C. B. Comstock, Henry Draper, Wolcott Gibbs, B. A. Gould, Henry, Hilgard, Lovering, Meigs, Mendenhall, Michelson, Morley, Newcomb, H. A. Newton, C. S. Peirce, Saxton, Sellers, W. P. Trowbridge, Webster, R. S. Woodward, Young.
In regard to the subject-matter which the original Committee No. 1 was to consider, Professor Bache remarked in his first report as President of the Academy (1863), as follows:
“It is not a little strange in our country, where the decimal system of coinage proved at once acceptable, notwithstanding the capital errors committed in, for a long time, keeping in use foreign coins of no convenient relation to the decimal system, that nothing of the kind was effected for weights and measures, and still more strange that the antiquated and cumbrous variety of tables by which articles of different classes were bought and sold should have been retained, that even in our preparation of a national system intended for practical use neither the decimalization of the weights and measures nor the simplicity of one weight of one name should have been adopted. The influence of great names can alone probably explain this, without justifying it.” [Rep. Nat. Acad. Sci. for 1863, p. 4.]
The proceedings of the committee were not reported in full, but Professor Bache informs us that “the discussions in the body of this committee were strongly in favor of the adoption of the French metrical system, but more strongly, in fact unanimously, in favor of the effort to arrive at a thorough international system—a universal system of weights, measure, and coins, available for the general acceptance of all nations.” [Loc. cit.]
It will readily be understood that the committee was not prepared to submit at once a general report on so comprehensive and important a matter. They adopted the plan of dividing into subcommittees, each of which should inquire into the system of weights and measures employed by one or more countries. Hav-ing made known this arrangement to the Academy on January 9, 1864, the committee was continued, with power to act. Two years later, on January 27, 1866, the committee submitted its first definite report in the following terms:
“Report of the Committee on Weights, Measures, and Coinage, to the National Academy of Sciences, January, 1866.
“The Committee are in favor of adopting, ultimately, a decimal system; and, in their opinion, the metrical system of weights and measures, though not without defects, is all things considered, the best in use. The Committee therefore suggest that the Academy recommend to Congress to authorize and encourage by law the introduction and use of the metrical system of weights and measures; and that with a view to familiarize the people with the system, the academy recommend that provision be made by law for the immediate manufacture and distribution to the custom-houses and States of metrical standards of weights and measures; to introduce the system into the post offices by making a single letter weight fifteen grammes instead of fourteen and seventeen hundredths or half an ounce; and to cause the new cent and two-cent pieces to be so coined that they shall weigh, respectively, five and ten grammes, that their diameters shall be made to bear a determinate and simple ratio to the metrical unit of length.” [Rep. Nat. Acad. Sci. for 1865, p. 5.]
This report was considered by the Academy and was transmitted to the Secretary of the Treasury, Hugh McCulloch, with a letter, signed by Joseph Henry, Vice-President of the Academy, giving the views of the majority and minority on the general question under consideration. This very interesting communication was as follows: [Loc. cit., p. 4]
“Sir: I have the honor herewith to transmit a report of the National Academy of Sciences on weights, measures, and coinage, adopted at its late meeting in January, after considerable discussion, but not with entire unanimity.
“The subject is one of much perplexity. While, on the one hand, it is evident that a reform of our present system of weights and measures is exceedingly desirable, on the other, the difficulty of adopting the best system and of introducing it in opposition to the prejudice and usages of the people is also apparent.
“The entire adoption of the French metrical system involved the necessity of discarding our present standard of weights and measures - the foot, the pound, the bushel, the gallon - and the introduction in their place of standards of unfamiliar magnitudes and names.
”Such a change, in my opinion, can only be, in a government like ours, the work of time and through the education of the rising generation, for this purpose, should the resolution now before Congress to establish a bureau of education be adopted, the French metrical system might be taught under the sanction of the government in all the common schools of the country.
“The system, however, is not considered by many as well adapted to the Anglo-Saxon mind as one which might be devised, and it was therefore the opinion of a minority of the academy, that, could England and the United States agree upon a system for adoption, it would in all probability in time become universal.
“The argument in favor of the French metrical system is, however, that it has been already adopted in whole or in part in several nations.
“I have the honor to be, your obedient servant,
“Vice President of the National Academy of Sciences.”
The recommendations of the Academy reached Congress either through the President or the Secretary of the Treasury, and were printed in the report of the House Committee of the 39th Congress on Coinage, Weights and Measures on the bills relating to the metric system then pending. This report begins as follows:
“In considering the general subject of a uniform system of coinage, weights and measures, your committee had before them -
“First. That part of the message of the President and accompanying documents relating to these subjects.
“Second. The report of the National Academy of Sciences, embracing their resolutions approving the metric decimal system of weights and measures.
“Third. The report of the United States commission to the statistical congress at Berlin [Hon. Samuel B. Ruggles.]
“Fourth. Various memorials of universities and colleges of the United States, urging a uniform system of weights and measures, also invariably commending the metric decimal system.
“Fifth. The petition of the mayor, judges, and citizens of Baltimore praying for the adoption of the metric system of weights and measures.
“Sixth. Several memorials of citizens in different parts of the United States in behalf of the same object.
“Seventh. The bill H. R. no. 252, referred to them, and proposing the compulsory and exclusive use after a limited period, of the metric system…”…
They also received the assistance of those distinguished members of the National Academy of Sciences who constitute the special committee of that learned society having charge of these subjects, and particularly Professor Newton, of that committee, whose efforts in aid of their purposes have been patient and persevering.” [House of Representatives, 39th Congress, 1st Session. Report no. 62. Coinage, Weights and Measures. (To accompany bills House Res. Nos. 596 and 597, and House Res. No. 141.) May 17, 1866. Ordered to be printed. p. 1.]
After this follows a resume of the history of the coinage, weights and measures of the United States, Great Britain and France, and a comparison of the existing weights and measures with the metric system. Finally, on page 20 of the report of the House Committee it is said: “Your committee unanimously recommend the passage of the bills and the joint resolutions appended to this report. They were not prepared to go, at this time, beyond this stage of progress in the proposed reform.” The reasons are then given and the report concludes with a list of the bills recommended. These are as follows:
“A bill making it lawful to use the metric system.
“A joint resolution directing the Secretary of the Treasury to furnish metric standards to the States.
“A bill to authorize the use in the post offices of weights of the denomination of grams.
“A joint resolution to authorize the President to appoint a special commissioner to facilitate the adoption of a uniform coinage between the United States and foreign countries.”
The bills legalizing the use of the metric system, directing the Secretary of the Treasury to furnish metric standards to the States, and authorizing the use in post-offices of weights of the denomination of grams passed the House on May 17, 1866, without discussion.
 They were brought up in the Senate on July 27, 1866, by Senator Sumner, who made a speech on their merits, and were passed on that day without discussion. The last two above mentioned were approved on the same day, July 27, 1866, and the first on July 28, 1866.
Thus, it appears that in this instance the recommendations of the Academy were received and accepted by Congress, and that the action taken was in accord therewith. It is clearly a case in which the Academy helped the Government.
At the same time at which the use of metric measures was legalized, Congress enacted a law enabling the Secretary of the Treasury to supply a set of the standards to each of the States of the Union. The Secretary requested the National Academy to advise him as to the kind and form of standards that should be furnished, the material of which they should be made, and the proper means of verifying them. The request was referred to the Committee on Weights and Measures which reported to the Academy at the meeting of August, 1867. The report was transmitted to the Treasury Department and the recommendations which it contained were adopted. [Rep. Nat. Acad. Sci. for 1879, p. 13.]
Congress passed a third act at the same time with the other two, as we have seen, authorizing the use in post-offices of weights of the denomination of grams. The Academy appears not to have been directly concerned in the passage of this measure, but at the annual meeting of the following year (1867) a resolution was adopted to the effect that the Academy considered it “highly desirable that the discretionary power granted by Congress to the Postmaster-General to use the metrical weights in the post offices (should) be exercised at the earliest convenient day.” As we have noted in a previous chapter, a committee was appointed in 1868 to urge upon the Postmaster-General the importance of adopting the action mentioned in this resolution, but no results followed at that time.
The interest of the National Academy in metric measures did not end with these proceedings. It will be recalled that two  international conferences were held in Paris to consider the question of preparing new metric standards, one in 1870 and the second in 1872. In this connection a proposition was put forward for the establishment of an international bureau of weights and measures, and the matter was submitted to various governments including that of the United States for consideration. It was brought by the Secretary of the Treasury on March 7, 1873, to the attention of the Academy which in turn referred it to the Committee on Weights and Measures. On June 13 of that year a report was transmitted to the Treasury Department.
Two years later, in 1875 the metric convention at Paris voted for the establishment of an international metric bureau and in April of that year, as was noted in an earlier chapter, the Academy adopted resolutions proclaiming its belief in the usefulness of such a bureau, and its “solicitude that the Government of the United States should ratify the convention prepared to that effect.” [Rep. Nat. Acad. Sci. for 1879, p. 13.] A copy of the resolutions was transmitted to the President, with a request for his favorable consideration. This letter was as follows: [Proc. Nat. Acad. Sci., vol. I, p. 111.]
“National Academy of Sciences,
“Washington, May 3, 1875.
“To the President:
“SIR: I have the honor to transmit to you herewith, in conformity with a resolution of the National Academy of Sciences, the expression of their opinion of the usefulness of an International Bureau of Weights and Measures, which is now the subject of a diplomatic conference at Paris, and of their solicitude that this Government should ratify the convention which has been prepared to that effect, and to ask your favorable consideration of the same.
“Very respectfully, your obedient servant,
“President National Academy of Sciences.”
“Upon this recommendation the convention was ratified by the United States Senate.” [Rep. Nat. Acad. Sci. for 1879, p. 13.] It was signed at Paris, May 20, 1875, the United States being the first to sign. [Encycl. Amer., vol. 10, 1904, article Metric System.]
 Further action in regard to the metric system was taken by the Academy in 1879, besides that mentioned on the preceding pages. This was in the form of resolutions urging that instruction in the principles of the metric system be introduced into the schools and colleges, that laws be enacted by Congress requiring the use of metric weights in the domestic mail service, and that the weights of coins be expressed in grams and milligrams rather than in grains and fractions of grains.