Sentence:  ... the asswagement of his discontent consists in two things, formerly prescribed as remedies against corporeall pain; "viz." Diversion of his thoughts from his losse, or the cause of it, and an application of them to those things, which he knowes to be <WSD>gratefull</WSD> and pleasant to his mind. 
Meaning of the word marked with <WSD> tags:  Pleasing, welcome.