Wo IPO Gr FI RRO ITS 
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8 NATURE OF CAPITAL AND INCOME [Crap I 
§ 3 
In the definition of wealth were included two attributes: 
wealth is material; and, it is owned. These attributes, 
materiality and appropriation, need to be considered sepa- 
rately. The remainder of this chapter will be devoted to 
the former. 
An important and useful result of the materiality of 
wealth is that it provides a basis for the physical measure- 
ment of wealth. Wealth is of many kinds, and each kind 
is measured in its own proper physical unit. These units 
have been handed down to us from various sources and in 
great diversity, but all of them are in the last analysis 
arbitrary. 
Many kinds of wealth are measured by weight-uniis. 
This is true of coal, iron, beef, and in fact, of most 
“commodities.” Each unit consists of the weight of 
some particular piece of matter which is adopted for con- 
venience as a standard. For instance, the English pound is 
simply a lump of platinum kept in London and called ar- 
bitrarily the pound. 
Many articles are not so conveniently measured by 
weight-units as by space-units, whether of volume, area, or 
length. Thus we have, for volume, milk measured by the 
quart, wheat by the bushel, wood by the cord, and gas by 
the cubic foot ; for areas, we have lumber sold by the square 
foot and land by the acre; for length, we have rope, wire, 
ribbons, and cloth measured in feet and yards. All these 
units of length, area, and volume are also quite arbitrary 
or conventional. The definition of the English yard, for 
instance, is an imaginary line drawn between two small 
dots on gold plugs in a particular brass rod in London. 
Many articles exist in more or less definite units which 
need only to be counted, as for instance, eggs or oranges, 
which are measured by the dozen. Similarly, writing paper 
is reckoned by the quire; pencils and screws by the gross.