The weight of a cubic decimetre of water reaches 1000 grammes under a pressure of four atmospheres; but in vacuo, at all temperatures, the weight of water is less than a kilogram.
The two standards, the cubic inch and the cubic decimetre, may not be strictly comparable owing to a difference in the normal temperature (Centigrade and Fahrenheit scales) of the two units of extension, the metre and the yard.
For the weight of the cubic decimetre of water, as deduced from the experiments made in London in 1896 as to the weight of the cubic inch of water, D.
(b) In determinations of volume which do not admit of a high degree of accuracy the cubic decimetre can be taken as equivalent to the litre; and in these determinations expressions of volumes based on the cube of the unit of linear measure can be substituted for expressions based on the litre as defined above.
For the specific mass of the cubic decimetre of water at 4° C., under an atmospheric pressure equal to 760 mm., Guillaume and Chappuis of the Comite International des Poids et Mesures at Paris (C.I.P.M.) have obtained 0.9999707 kg., which has been accepted by the committee.