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Pennock v. Dialogue

Pennock v. Dialogue

In the
Pennock v. Dialogue case from 1829, Pennock (the plaintiff) was seeking a
patent for improvements for making hoses he created but which were already
being used by the public. The court ruled in favor of the defendant on the
issue of patenting items already in the public’s possession. The case was heard
in the Circuit Court for the Eastern District of Pennsylvania.

Case Description

Pennock and Sellers created a new method for producing
hoses to transport air, water and other fluids. They did not patent their new
method when it was created in 1811. The public soon got hold of the new method
for the improved art of making hoses and 13,000 feet of hose had been
constructed in houses in Philadelphia. Samuel Jenkins claimed to have an
agreement with the plaintiffs to sell and supply hoses to hose companies in

Once the
hose companies began producing hoses using the plaintiff’s method the invention
was in the possession of the public and were subject to public use. The
plaintiff made no claim that from 1811 to the time they were ready to apply for
an invention patent that they were improving their hose-making method. The
plaintiffs did not claim to try and hide the new method of making hoses from
the public.


The jury in this case ruled once an inventor
willfully gives up their exclusive rights after an invention is created and a
patent is not obtained, they cannot regain any rights once the public is in
possession of those rights. An invention that is in the public domain cannot be
taken out of that domain. Once an invention is legally open for public use it
cannot be taken away because that would disrupt any growth or room for
improvement within that invention. 

If the plaintiffs had successfully obtained
an invention patent for their improvement to hose production they would have
had a valid claim against those profiting off of their improved hose production

This case showed the importance of obtaining a patent.
Inventing something and being recognized as the creator does not offer enough
protection and rights to assure that the inventor will be the main person
profiting off of their invention. If the public gets hold of the knowledge or a
method for improvement before a patent is acquired, a patent request will be
denied because the invention is a part of public domain.