probable, however, that the very rich do not pay as much
as they ought to do. At the same time those who are too poor to pay
income tax, and who do not drink nor smoke, are almost entirely free
from taxation in this country; they pay very little, except poor rates.
It would be impossible to invent any one tax which could be equally
levied upon all persons. The income tax is a tax of so many pence in
every pound of a person's income, but it is impossible to make people
state their income exactly, and poor people could never be got to pay
such a tax. Hence it is necessary to put on a certain number of
different taxes so that those who manage to escape one tax shall be made
to pay in some other way.

(2) The tax which each individual is bound to pay ought to be certain,
and not arbitrary. The time of payment, the manner of payment, the
quantity to be paid, ought all to be clear and plain. This is the #maxim
of certainty#, and it is very important, because, if a tax is not
certainly known, the tax-gatherers can oppress people, requiring more or
less as they choose. In this case it is very probable that they will
become corrupt, and will receive bribes to induce them to lower the tax.
On this account duties ought never to be levied according to the value
of goods, or _ad valorem_, as it is said. Wine, for instance, varies in
value immensely according to its quality and reputation, but it is
impossible for the custom-house officer to say exactly what this value
is. If he takes the statement of the people who import the wine, they
will be tempted to tell lies, and say that the value is less than it
really is. And as it would not be easy to prove the guilt either of the
customs officer or of the importers, it is to be feared that some
officers will receive bribes. But if the wine is taxed simply according
to its quantity, the amount of duty is known with great certainty, and
fraud can easily be detected. The same remarks apply more or less to
every kind of goods which varies much in quality.

(3) Every tax ought to be levied at the time, and in the manner, in
which it is most likely to be convenient for the contributor to pay it.
This is #the maxim of convenience#, and the reason for it is
sufficiently obvious. As government only exists for the good of the
people at large, of course it ought to give the people as little trouble
as possible. And as the Government has immensely more money at its
command than any private person,