A.) Battery: The wrong of battery consists in the intentional application of force to another person without any lawful justification. The essential requirements are, a.) Use of force, b.) The use of such force must be without any lawful justification.
Touching someone in aggression may also be constituted as battery. Causing someone physical discomfort without directly touching, such as inflection of heat, light, electricity or gas etc. can still fall under the category of ‘use of force’ and constitute battery. The use of force in either case, should be intentional and without lawful justification for it to be considered as battery.
However, Mere passive obstruction cannot be considered as a use of force. Example: In Innes V. White, a policeman although unlawfully prevented the plaintiff from entering into a club, he did not make use of any force but was merely passive like a door or wall to prevent the plaintiff from entering the premises and hence it did not constitute battery. Also, harm suffered voluntarily cannot be considered as battery.
B.) Assault: It is an act of the defendant that causes to the plaintiff reasonable apprehension of the infliction of battery on him by the defendant. Apprehension is defined as a worry or fear that something unpleasant may happen. In simple words when a person (defendant) creates an apprehension in the mind of another person (plaintiff) by his act, that he is going to commit battery against the person, an assault is said to be committed. The essential requirements are that there should be a reasonable apprehension created that immediate force will be used.
Pointing a loaded gun at someone may be considered as an act of assault.
Generally, assault precedes battery. The act of showing clenched fists to someone is an act of assault and actually striking it will amount to battery. It is also not necessary that every battery should include assault in the first place.