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Final Answers
© 2000-2003 Gérard P. Michon, Ph.D.

1819 Report on Weights & Measures

Below is the preliminary report on the British reform eventually enacted in 1824, noted for its introduction of the Imperial gallon as the volume of 10 pounds of water at 62°F.

This report was first posted the day of its 184th anniversary on


First Report (1819) of the Commissioners
Appointed to Consider Weights and Measures

MAY IT PLEASE YOUR ROYAL HIGHNESS,  We, the Commissioners appointed by Your Royal Highness, for the purpose of considering how far it may be practicable and advisable to establish, within His Majesty's dominions, a more uniform system of WEIGHTS AND MEASURES, having obtained such information as we have been able to collect, beg leave to submit, with all humility, the first results of our deliberations.

I.   We have procured, for the better consideration of the subject referred to us, an abstract of all the Statutes relating to Weights and Measures, which have been passed in the United Kingdoms from the earliest times; and we have obtained from the County Reports, lately published by the Board of Agriculture, and from various other sources, a large mass of information respecting the present state of the customary Measures employed in different parts of the United Kingdom.  We have also examined the Standard Measures of Capacity kept in the Exchequer, and we have inquired into the state of the Standards of length of the highest authority.  Upon a deliberate consideration of the whole of the system at present existing, we are impressed with a sense of the great difficulty of effecting any radical changes, to so considerable an extent, as might in some respects be desirable; and we therefore wish to proceed with great caution in the suggestions which we shall venture to propose.

II.   With respect to the actual magnitude of the Standards of Length, it does not appear to us, that there can be any sufficient reason for altering those, which are at present generally employed.  There is no practical advantage, in having a quantity commensurable to any original quantity, existing, or which may be imagined to exist, in nature, except as affording some little encouragement to its common adoption by neighbouring nations.  But it is scarcely possible, that the departure from a Standard, once universally established in a great Country, should not produce much more labour and inconvenience in its internal relations, than it could ever be expected to save in the operation of Foreign commerce and correspondence, which always are and always must be conducted by persons, to whom the difficulty of calculation is comparatively inconsiderable, and who are also remunerated for their trouble, either by the profits of their commercial concerns, or by the credit of their scientific acquirements.

III.   The subdivisions of Weights and Measures, at present employed in this Country, appear to be far more convenient for practical purposes than the Decimal Scale, which might perhaps be preferred by some persons, for making calculations with quantities already determined.  But the power expressing a third, a fourth, and a sixth of a foot in inches, without a fraction, is a peculiar advantage in the Duo-decimal Scale; and, for the operations of weighing and of measuring capacities, the continual division by Two renders it practicable to make up any given quantity, with the smallest possible number of standard Weights or Measures, and is far preferable, in this respect, to any decimal scale.  We would therefore recommend, that all the multiples and subdivisions of the Standards to be adopted should retain the same relative proportions to each other, as are at present in general use.

IV.   The most authentic standards of Length, which are now in existence, being found, upon a minute examination, to vary in a very slight degree from each other, although either of them might be preferred without any difference that would become sensible in common cases; we beg leave to recommend, for the legal determination of the standard Yard, that which was employed by General Roy, in the measurement of a base on Hounslow Heath, as a foundation for the trigonometrical operations that have been carried on by the Ordnance throughout the country, and a duplicate of which will probably be laid down on a Standard Scale, by the Committee of the Royal Society, appointed for assisting the Astronomer Royal, in the determination of the length of the pendulum; the temperature being supposed to be 62 degrees of Fahrenheit, when the scale is employed.

V.   We proposed also, upon the authority of the experiments made by the Committee of the Royal Society, that it should be declared, for the purpose of identifying or recovering the length of this standard, in case that it should ever be lost or impaired, that the length of a pendulum vibrating seconds of mean solar time in London, on the level of the sea, and in a vacuum, is 39.1372 inches of this scale; and that the length of the metre employed in France, as the ten millionth part of the quadrantal arc of the meridian, has been found equal to 39.3694 inches.

VI.   The definitions of measures of Capacity are obviously capable of being immediately deduced from their relations to measures of Length; but since the readiest practical method of ascertaining the magnitude of any measure of capacity is to weigh the quantity of water which it is capable of containing, it would, in our opinion, be advisable in this instance to invert the more natural order of proceeding, and to define the measures of Capacity, rather from the weight of the water they are capable of containing, than from their solid content in space.  It will therefore be convenient to begin with the definition of the Standard of Weight by declaring, that nineteen cubic inches of distilled water, at the temperature of 50°, must weigh exactly ten ounces Troy, or 4,800 grains; and that 7,000 such grains make a pound avoirdupois; supposing, however, the cubic inches to relate to the measure of a portion of brass, adjusted by a standard scale of brass.  This definition is deduced from some very accurate experiments of the late Sir George Shuckburgh, on the Weights and Measures of Great Britain; but we propose at a future period to repeat such of them as appear to be the most important.

VII.   The definitions thus established are not calculated to introduce any variation from the existing standards of Length and of Weight, which may be considered as already sufficiently well ascertained.  But, with respect to the measures of Capacity, it appears, from the report contained in the Appendix (A) that the legal standards of the highest authority are considerably at variance with each other: the Standard gallon, quart and pint of Queen Elizabeth, which are kept in Exchequer, having been also apparently employed, almost indiscriminately, for adjusting the measures both of corn and of beer; between which, however, a difference has gradually, and as it may be supposed, unintentionally crept into the practice of the Excise; the ale gallon being understood to contain about four and a half per cent more than the corn gallon, though we do not find any particular act of parliament in which this excess is expressly recognised.  We think it right to propose that these measures should again be reduced to their original equality; and at the same time, on account of the great convenience which would be derived from the facility of determining a gallon and its parts, by the operation of weighing a certain quantity of water, amounting to an entire number of pounds and ounces without fractions, we venture strongly to recommend, that the Standard Ale and Corn Gallon should contain exactly ten pounds Avoirdupoids of distilled water, at 62° of Fahrenheit, being nearly equal to 277.2 cubic inches, and agreeing with the Standard pint in the Exchequer, which is found to contain exactly twenty ounces of water.

VIII.   We presume that very little inconvenience would be felt by the Public, from the introduction of this gallon, in the place of the customary Ale Gallon of 282 cubic inches, and of the Winchester corn gallon, directed by a Statute of King William to contain 269, and by some later statutes estimated at 272¼ cubic inches; especially when it is considered that the standards, by which the quart and pint beer measures, used in London, are habitually adjusted, do not at present differ in a sensible degree from the standard proposed to be rendered general.  We apprehend also, that the slight excess of the new bushel, above the common corn measure, would be of the less importance, as the customary measures, employed in different parts of Great Britain, are almost universally larger than the legal Winchester Bushel.

IX.   Upon the question of the propriety of abolishing altogether the use of the wine gallon, and establishing the new gallon of ten pounds, as the only standard for all purposes, we have not yet been able to obtain sufficient grounds for coming to a conclusive determination; we can only suggest, that there would be a manifest advantage in the identification of all measures of the same name, provided that the change could be made without practical inconvenience: but how far the inconvenience might be more felt than the advantage, we must leave to the wisdom of His Majesty's Government to decide.

X.   In the meantime it may be advisable to take into consideration the present state of the numerous and complicated Laws, which have been enacted at various times for the regulation of the Weights and Measures employed in commerce; and the Abstract of these Laws, which we have prepared, will be found in the Appendix (B) of this Report.  We must, however, reserve, for a future occasion, the information which we have procured respecting the customary Weights and Measures of the different Counties, as we have not yet been able to reduce our Abstract into the most convenient form, for affording a connected view of this branch of the subject referred to us.

24 June 1819


Appendix A


Appendix B

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