"It is essential to the validity of a patent that the complete
specification should sufficiently and fairly describe and ascertain
the nature of the invention and the manner in which the
invention is to be performed : in other words, that the patentee
should disclose his invention sufficiently to enable those who
are skilled in the relevant art to utilize the invention after
the patentee's monopoly has come to an end. Such disclosure
is, indeed, the consideration that the patentee gives for the
grant to him of a monopoly during the period that the patent
would run. Another essential to the validity of the patent is
that the complete specification should sufficiently and clearly
ascertain the scope of the monopoly claimed. The reason for
that is in order that those who are engaged in the art may
know how far they can go without running the risk of having
an action for infringement of the patent started against them
by the patentee. If the complete specification does not clearly
indicate the ambit of the invention, it will redound, to use the
words of s. 6 of the Statute of Monopolies, 'to the hurt of trade,
and be generally inconvenient'. One might put it a great
deal more strongly - the patent will be a public nuisance,
hindering and embarrassing those persons engaged in the
particular art, from carrying on their legitimate trade or
business."