been free from any fault in creating the danger. So, an engineer who stays at his post to save passengers from a collision is not to be deemed guilty of contributory negligence, unless, for instance, he violated orders in starting and thereby brought on the collision.

§ 178. Persons of defective powers.-As has been shown, persons of defective powers are not guilty of negligence for failing to exercise more care than they are capable of exercising. This is equally true where the question is upon contributory negligence of such persons. It naturally follows that a correspondingly higher degree of care is required from all who deal with such persons. An act that would be ordinarily careful, if done toward a grown person, might be negligent if done toward a child. It is always presupposed, however, that the defective condition of the person was or ought to have been known. Thus an engineer would not be negligent for expecting a man to step off the track when he sounded the whistle, without checking speed, whereas, if he had notice that the man was deaf, it would be negligence.

§ 179. Misleading conduct.-A plaintiff is not chargeable with contributory negligence, whose erroneous act was caused or induced by the misleading conduct of the defendant. If he has a right to rely and does rely upon defendant's verbal directions or conduct, assuring him of safety, he is blameless, provided the danger is not obvious; and where by the defendant's negligence a sudden danger confronts the plaintiff, he is not in fault if in the haste and alarm he does not choose the safest course, or even if he chooses the only dangerous course.

§ 180. Imputable negligence. The principle on which the doctrine of imputable negligence rests is that

the innocent person and the guilty person are identified as in a joint enterprise, by agency or by having the right to control. The case of saver and saved has been alluded to, the negligence of the one saved being imputed to the saver. The negligence of a servant is imputed to the master, for he has the right to control. Partners, whose goods are injured by negligence of another, can not recover if the negligence of one partner contributed, for his negligence is imputable to all. The cases of carrier and passenger, and of children, require a few words.

more.

§ 181. Passenger and carrier-Imputed negligence. -The old English rule, established by the case of Thorogood v. Bryan, was that in an action by a passenger against a third person for a negligent injury, the contributory negligence of the carrier will be imputed to the passenger. It was assumed that a carrier is a passenger's servant in all cases. The rule has been overthrown in England, and is not in force in the United States courts, nor in most of the states. The negligence will not be imputed to the passenger unless the driver was acting under the direct control and instruction of the passenger. This is the modern view.

§ 182. Children-Imputed negligence.-The question is only concerning children too young to be capable of exercising any care whatever; for if they have any capacity at all they will be negligent for failing to exercise it, and at the same time will be responsible only for their own negligence. Whether the negligence of parents or custodians shall be imputed to children who are themselves incapable of exercising care and hence incapable of negligence, is a question upon which the authorities

are divided. The better reason is against imputing negligence in such case.

§ 183. Presumptions as to negligence.-As a rule negligence is not presumed, but must be proved. The mere fact that some one has been injured does not usually make it probable that any particular person has been negligent. But the circumstances under which an injury occurred may be such as to create a presumption of negligence, and throw the burden upon a certain person to prove himself without fault. If, judged by common human experience, a fact could not exist except by some negligence, the court will, in the absence of other evidence, declare that there was negligence. For instance, if a passenger is thrown down by the jerk of a street car, the presumption is that the jerk was by negligence of the street car company; if a boiler on a vessel explodes, it is presumed to have exploded by negligence of those in control. The presumption can always be overcome by the defendant showing that in fact he exercised ordinary care under the circumstances.

Whether the presumption shall be made depends somewhat upon the nature of the duty owing and the degree of care required in its discharge. Where there is an obligation for especial care, the presumption of negligence will be made, when it would not under ordinary circumstances. For example, if a railroad train runs off the track and injures a passenger and a bystander, as to the passenger the presumption of negligence in the railroad company would arise, but not as to the bystander.

9-Elem. Law.

§ 184. Incorporeal

hereditaments.- Incorporeal

hereditaments are inheritable, but intangible rights in corporeal or tangible property, such as rights of way across the land of another, easements and the like. These rights partake of the nature of the things out of which they issue, but, since the rights themselves can not be seen or handled, it is evident that they are incapable of direct injury. Whatever injury is done must be consequential. Hence the remedies for direct wrongs against corporeal property are not applicable to incorporeal hereditaments. If one has a right of way across another's land, and it is interfered with so that he is deprived of its use, his remedy is not by ejectment, but by an action for the consequential damages or by an injunction. But where the consequence of a wrong to an incorporeal right is also an injury to corporeal property, the remedies as for a direct wrong may be had. For instance, if a landowner has an easement for lateral support, and his neighbor wilfully and maliciously takes away the support and causes the land to fall, the owner may treat it as a direct wrong done by force to his land.

§ 185. Other incorporeal rights.-There is an im

portant class of incorporeal rights which do not issue out of corporeal property in the sense that incorporeal hereditaments do. This class embraces the subjects of copyrights, patents and trademarks. Public policy and the sense of justice dictate that one who creates anything should be permitted to enjoy the fruits of his labors. It is evident that in case of copyrights, patents and trademarks, the substantial benefit to be derived by the creator of the thing in question lies in his having the exclusive right to reproduce or use it.

§ 186. Statutory provisions.-The constitution of the United States gives power to congress to secure to authors and inventors the benefit from their creations, for a limited time; and congress has passed acts for that purpose. Just what the provisions are as to the steps to be taken, it is not now material to inquire. Whenever the formalities prescribed are observed the writer or inventor has a monopoly for the period provided, and may have his remedy against one who infringes his right. He may procure an injunction, recover damages he has suffered, and recover profits made by others.

§ 187. Patents.-Without entering into the details of patent law, a few general principles may be stated. A patent is given for an invention, namely something created by man. Natural processes and principles can not be patented. The thing must be new and useful. A new method of combining things to produce results may be patented.

Infringement of patents may consist in making, using or selling the thing that is substantially covered by the patent. The person infringing may be held liable, whether he knew or did not know the article was patented.