According to the present patent laws, it is more than questionable whether the discoverer of a great scientific principle could pursue his own discovery, or whether he would not be arrested on the threshold by a subsequent patentee; if Jacobi lived in constitutional England instead of despotic Russia, it is doubtful if he could work out his discovery of the electrotype--we say _doubtful_; for, as far as we can learn, it seems hitherto judicially undecided whether the mere use of a patent, not for sale or a lucrative object, is such a use within the statute of James as would be an infringement of a patentee's rights. It appears to be settled, that a previous experimental and unpublished use by one party, does not prevent another subsequent inventor of the same process from patenting it; and, by parity of reasoning, we should say, that if a party have the advantage of patenting an invention which can be found to have been previously used, but not for sale, he should not have the additional privilege of prohibiting the same party, or others, from proceeding with their experiments. There are, however, not wanting arguments for the other view. The practice of a patented invention, for one's own benefit or pleasure, deprives the patentee of a possible source of profit; for it cannot be said that the party experimenting, if prohibited, might not apply for a license to the patentee. Take, for instance, the notorious and justly censured patent of Daguerre. Supposing, for argument's sake, this patent to be valid, can a private individual, under the existing patent laws, take photographic views or portraits for his own amusement, or in pursuance of scientific investigations? If he cannot, then is an exquisitely beautiful path of physics to be shut up for fourteen years; or if he can, then is the licensee, a purchaser for value, to be excluded from very many sources of pecuniary emolument? To us, the injury to the public, in this and similar cases, appears of incomparably greater consequence than that to the individual; but what the authorities at Westminster Hall may say is another question. Even could the patent laws be so modified, that the benefits derived from them could fall upon those scientific discoverers most justly entitled, we are still doubtful as to their utility, or whether they would contribute to the advancement of science, which is the point of view in which we here principally regard them. It would scarcely add to the dignity of philosophy, or to the reverence due to its votaries, to see them running with their various inventions to the patent office, and afterwards spending their time in the courts of law, defending their several claims. They would thus entirely lose the respect due to them from their contemporaries and posterity, and waste, in pecuniary speculation, time which might be more advantageously, and without doubt more agreeably, employed. If parties look to money as their reward, they have no right to look for