came before the High Court in Chaplin's Case (1). The Act
merely declared, in accordance with the above suggestion of
Griffith C.J., that " the taxation by a State, in common with other-
salaries earned within the State " of the salaries earned in the State
by Commonwealth officers should not, if the quantum of tax was
not higher than that imposed on salaries of the same amount earned -
in the State, "be deemed . . . an interference with the exercise
of any power of the Commonwealth."
It will be observed that the legislation did not purport to authorize
a State to tax Commonwealth officers' salaries. Accordingly the .
argument that, under sec. 109 of the Constitution, a Commonwealth
law providing a salary for a Commonwealth officer was inconsistent
with a State law taxing that salary (in common with others) still
remained open to the taxpayer. It was not employed, nor was any
reference made to sec. 109 in the judgment. This again shows that
the only ground upon which Griffith C.J., Barton and O'Connor JJ. -
(Isaacs and Higgins JJ. did not sit in Chaplin's Case) thought
invalidity could attach to the operation of State income tax legisla-
tion against salaries of Commonwealth officers was that of the -
" implied immunity of Commonwealth (and State) instrumentalities,"
and that immunity was not a personal right of the servant, but a
right of the Government, which could waive it by appropriately -
worded legislation (2).
In Chaplin's Case (2) the court said, in relation to the grant of
salaries :
"The grant, if no more is said, is free from taxation by the State, but in making
the grant the Commonwealth may say that the grant to the individual is
subject to State taxation "
This passage also is concerned only with the doctrine of immunity
of instrumentalities, and cannot be used as any justification for the
theory that, unless grants of Commonwealth salaries or pensions are
expressly subjected to general income tax legislation of a State,
sec. 109 should be deemed to invalidate the State legislation so far
as applicable to such salaries or pensions.
The Engineers' Case.
The general doctrine of immunity of instrumentalities had numerous
and startling applications before it was overthrown in the Engineers'
Case (3). As Higgins J. said in 1925,