of mixed law and fact was not permissible and even if it were
permissible it could only be evidence of the fact alleged and not
the law. The difficulties of analysing a mixed statement of law
and fact referred to in Ex parte O'Sullivan; Re Craig (1) were
adverted to in Jackson y. Butterworth (2). If matters of mixed
Jaw and fact are averred then if the matters of fact cannot be
segregated from the matters of law there is no evidence of the facts
averred. The onus was on the appellant to establish beyond
reasonable doubt the matters charged against the respondent.
The onus was also upon the appellant to segregate from the aver-
ments the matters of fact upon which he relied. The appellant
has not in either respect discharged that onus. The determination
of what is gross income and what is not, necessarily involves a
construction of the Income Tax Assessment Act. The word " false "
as used may be false with knowledge or false without knowledge
on the part of the respondent. he first-mentioned meaning may
involve a question of law. The averments as to the amount
returned by the respondent as total gross income from his business
and the amount understated are matters of law. If, in order to
ascertain whether a matter averred is a question of mixed fact or
law, it is necessary to have resort to a statute and such statute
either defines the words or phrases used or extends the meaning
of such words or phrases, then the matter is one of law and not of
fact. It involves as a matter of law the resort to the Act and the
construction of the Act. For example, there is no difference
between gross income and assessable income and in order to deter-
mine what is assessable income it is necessary to refer, inter alia,
to ss. 6 (definitions), 25, 26, 262. To determine " profit" on the
disposal of the whole or part of a business reference to s. 36 (1)
is necessary, and in respect to the making of returns it is necessary
to refer to ss. 161 and 162. The words " public school" under
consideration in Girls' Public Day School Trust Ltd. v. Ereaut (3)
and " mining operations * under consideration in Federal Commis-
sioner of Taxation v. Broken Hill South Ltd. (4) were not defined
in the respective relevant statutes. Similarly, in The Common-
wealth v. Grunseit (5) the material words were not defined in the
relevant regulations. If an averment contains a word or words
which has or have been judicially pronounced upon, the appli-
cation of the particular pronouncement to the particular word or