The present publication is a sequel to my former one, on the Senses and the Intellect, and completes a Systematic Exposition of the Human Mind. The generally admitted but vaguely conceived doctrine of the connexion between mind and body has been throughout discussed definitely. In treating of the Emotions, I include whatever is known of the physical embodiment of each. The Natural History Method, adopted in delineating the Sensations, is continued in the Treatise on the Emotions. The first chapter is devoted to Emotion in general; after which the individual kinds are classified and discussed; separate chapters being assigned to the sthetic Emotions - arising on the contemplation of Beauty in Nature and Art - and to the Ethical, or the Moral Sentiment. Under this last head, I have gone fully into the Theory of Moral Obligation. It has been too much the practice to make the discussion of the Will comprise only the single metaphysical problem of Liberty and Necessity.