Note 30 — Chapter X · THE CUBIC FOOT AND THE TON REGISTER

For this reason the custodians of the metric system have abandoned the cubic decimetre of water as the basis of measures either of capacity or of weight. The kilogramme is now, like our pound, a certain metal standard, and the litre is a measure containing, more or less exactly, a kilogramme of water. A perfect litre standard contains 1000 grammes of water at 39·2°; but 1·1 gramme less at 62°, 2 grammes less at 70°, and 3·3 grammes less at 80°, a very frequent summer temperature. For exact correspondence of measure with weight, corrections are always required whether on the imperial or on the metric system.