Evidence as to document meaningless in reference to existing facts
97.  When language used in a document is plain in itself, but is meaningless in reference to existing facts, evidence may be given to show that it was used in a peculiar sense.
Illustration
     A conveys to B by deed “my plantation in Penang”.
     A had no plantation in Penang, but it appears that he had a plantation in Province Wellesley, of which B had been in possession since the execution of the deed.
     These facts may be proved to show that the deed related to the plantation in Province Wellesley.