What is the case law on “clear and decisive” meaning of a clause in an instrument?

The case seems to me to be eminently one for the application of the rule so forcibly enunciated in Thornhill v. Hall, 2 Cl. & F. 22, that “when an interest is given or an estate conveyed in one clause of the instrument in clear and decisive terms, such interest or estate cannot be taken away or cut down by raising a doubt upon the extent and meaning and application of a subsequent clause, nor by inference therefrom, nor by any subsequent words that are not as clear and decisive as the words of the clause giving that interest or estate.”