as to this
apparently simple problem. The common-sense solution would seem to be
that recommended by Sir Edward Hamilton, viz. to reckon the net revenue
as a tax and the balance of gross revenue as payment for services
rendered; although in view of the complications resulting from the
existence of unremunerative services, and the failure to make proper
allowance in respect of the capital employed in the service, such a
course is unscientific and misleading.

"The whole of the receipts from the various sources administered by the
Post Office has always been treated in our Public Accounts as 'Non-Tax
Revenue.' It is all carried to the Exchequer; and the whole cost is
annually provided by Parliament. Therefore, to omit altogether this
public receipt from a classification of taxes would seem to be the
natural course to take. But the charge which is made for the carriage of
letters, telegrams, and parcels, so far as the Post Office services are
a State monopoly, is unquestionably 'an obligatory contribution by
persons in respect of or incidental to something which they do.'
Accordingly, to take no account of this charge, which nobody can avoid,
would be to omit something which falls within our definition of a tax.
At the same time it is obvious that to treat the whole of the Post
Office revenue as a tax would for present purposes be misleading,
inasmuch as the amount actually expended by the State represents direct
and immediate service rendered to those who write letters or send
telegrams. Regard being had to these considerations, when balanced one
with another, it appears to me that the least incorrect course to adopt
is to treat as a tax the amount by which the revenue derived from Post
Office services exceeds the cost of administering those services."--Sir
E. W. Hamilton, K.C.B. (_Memoranda on Classification and Incidence_, p.
36).

See also p. 361, n. 2, _supra._

[752] "There cannot be devised a more eligible method than this of
raising money upon the subject; for therein both the Government and the
people find a mutual benefit. The Government acquires a large revenue,
and the people do their business with greater ease, expedition, and
cheapness than they would be able to do if no such tax (and of course no
such office) existed."--Sir William Blackstone, _Commentaries on the
Laws of England_, London, 1783, vol. i. p. 324.

"Nor, while the rates of postage are confined within due limits, or not
carried so high as