Since this was first written, the accident has happened. The standard yard was so injured as to be rendered useless by the fire at the Houses of Parliament.

The minute and second are often marked thus, 1′, 1″: but this notation is now almost entirely appropriated to the minute and second of angular measure.

The measures in italics are those which it is most necessary that the student should learn by heart.

The lengths of the pendulums which will vibrate in one second are slightly different in different latitudes. Greenwich is chosen as the station of the Royal Observatory. We may add, that much doubt is now entertained as to the system of standards derived from nature being capable of that extreme accuracy which was once attributed to it.

The inch is said to have been originally obtained by putting together three grains of barley.

‘Capacity’ is a term which cannot be better explained than by its use. When one measure holds more than another, it is said to be more capacious, or to have a greater capacity.

Since the publication of the third edition, the heaped measure, which was part of the new system, has been abolished. The following paragraph from the third edition will serve for reference to it: “The other imperial measure is applied to goods which it is customary to sell by heaped measure, and is as follows:

2 gallons 1 peck

4 pecks 1 bushel

3 bushels 1 sack

12 sacks 1 chaldron.

The gallon and bushel in this measure hold the same when only just filled, as in the last. The bushel, however, heaped up as directed by the act of parliament, is a little more than one-fourth greater than before.”

Pure water, cleared from foreign substances by distillation, at a temperature of 62° Fahr.

Farthings are never written but as parts of a penny. Thus, three farthings being ¾ of a penny, is written ¾, or ¾. One halfpenny may be written either as 2/4 or ½; the latter is most common.

Before reading this article and the next, articles (29) and (42) should be read again carefully.