How did John Stuart Mill distinguish deduction from induction?

In his System of Logic (1843), John Stuart Mill addressed the distinction between deductive and inductive reasoning, which are foundational to his methodology.1

Traditionally, deduction is defined as a process of inference where the conclusion follows necessarily from the premises, effectively drawing out propositions that were already latent within those premises.2

In contrast, Mill focused heavily on induction, which he viewed as a method of reasoning from particulars to generals or from the individual to the universal. To formalize this, he developed Mill’s methods—five techniques of experimental reasoning designed to identify causal connections between factors and their effects. These include:21

• Method of agreement: Identifying factors present whenever an effect occurs.1
• Method of difference: Comparing instances where an effect occurs versus when it does not to isolate a specific cause.1
• Joint method of agreement and difference: Combining the two previous approaches.1
• Method of residues: Attributing remaining effects to remaining circumstances after accounting for known factors.1
• Method of concomitant variation: Observing if variations in a factor correlate with variations in an effect.1