hat the said John Roe shall pay all moneys necessary
to the construction of a suitable model to represent the
said invention; that he shall pay all necessary expense in
advertising and bringing said invention before interested
parties (and such other clauses as may be deemed necessary
and agreed upon, such as the expense of constructing a
working model, or carrying out a process, etc.); that he
shall make diligent effort to promote the said invention,
its manufacture, and sale.

Second, That the said Richard Doe, sole owner of said
invention and Letters Patent, in consideration of the
payment of the moneys above mentioned, agrees to pay the
said John Roe twenty-five per cent. (or other amount agreed
upon) of all the net receipts in any manner arising from
the sale or working of the said Letters Patent, during the
term for which said patent is granted.

Witness our hands and seals this tenth day of January, A.D.
1901.

RICHARD DOE,
JOHN ROE.

In the presence of:
JOHN SMITH,
THOS. JONES.

[Sidenote: Perfecting Inventions.]

Should an inventor defer the filing of his application until his
invention is fully developed as regards the detail construction and
arrangement of the parts? The best opinion seems to be in favor of the
prompt filing of the application. The final form of the details can best
be determined by the manufacturer and expert machinists and designers,
who appreciate the matter of economical manufacture, which is quite as
essential as the efficiency of the device or machine. Clearly,
therefore, the inventor cannot decide as to all the details; why then
should he delay his application?

The safest course for an inventor is to file his application for a
patent as soon as his invention is complete in its principal features,
so as to conform to the requirement of the Patent Law that an invention
be sufficiently complete to be theoretically operative. The mechanical
details are rarely of great importance as far as the patentable
features of the invention are concerned. Still, it is well to give the
attorney full particulars of whatever details the inventor has in mind.

[Sidenote: Exhibit of the Invention.]

Under the security thus afforded for the main features involved in his
idea, the inventor can proceed more deliberately in perfecting and
improving his invention, and can then file an additional application if