A person engaged in manufacturing an article by a secret process may sell the business and secret, and make a valid promise not to divulge the secret to any one else, nor to engage himself at any time in manufacturing by that process. Such a restraint is necessary to protect the other party, and does not unduly prejudice the public. In speaking of such a contract, it was said by the New York court, in a late case, that it "simply left matters substantially as they were before the sale, except that the seller of the secret had agreed that she would not destroy its value after she had received full value for it. The covenant was not in general restraint of trade, but was a reasonable measure of mutual protection to the parties, as it enabled the one to sell at the highest price, and the other to get what he paid for. It imposed no restriction upon either that was not beneficial to the other by enhancing the price to the seller, or protecting the purchaser. Recent cases make it very clear that such an agreement is not opposed to public policy, even if the restriction was unlimited as to both time and territory." 33