[L R] 19 Eq 462 (1875)
SIR G. JESSEL, M.R.,: The buyers were about to form a company to work the invention, that means to produce tickets with numbers. That was to be their business. They were to produce and sell a commodity, the object of the invention being to produce that commodity more cheaply than had been done before. It was an old commodity, an old product, but had not been produced in the same manner before. The object of the company, therefore, was to sell the old product at a lower price than the price at which it could be produced by the modes in use before this invention was patented, and thereby to obtain business. That is the object. Being about to establish that company, and being about to buy the invention, they found the invention not in the exclusive hands of the inventor, but in the hands of himself and his assigns, persons who had acquired by purchase some portion of his patent rights.
Now nothing is better known than this, that when persons have turned their attention to a particular class of invention they are likely to go on and invent, and likely to continuously improve the nature of their invention, and continuously to discover new modes of attaining the end desired. Persons, therefore, who buy patents of inventors are in the habit of protecting themselves from the utter destruction of the value of the thing purchased by bargaining with the seller that he shall not use any new invention of his for producing that product in which they are about to deal at a cheaper rate, because if he were allowed to do so he might, the day after he had sold his patent, produce something which, without being technically an infringement, and without being technically an improvement, might accomplish the desired object in some other way, and utterly destroy the value of that which they had purchased. They, therefore, not unreasonably, and not unusually, make it a part of their bargain...