Money cannot be applied to the General Welfare, otherwise than by an application of it to some particular measure conducive to the General Welfare. Whenever, therefore, money has been raised by the General Authority, and is to be applied to a particular measure, a question arises whether the particular measure be within the enumerated authorities vested in Congress. If it be, the money requisite for it may be applied to it; if it be not, no such application can be made.