When language used in a document is plain in itself, and when it applies accurately to existing facts, evidence may not be given to show that it was not meant to apply to such facts.

Illustration.

   A sells to B, by deed, "my estate at Rampur containing one hundred bighas". A has an estate at Rampur containing one hundred bighas. Evidence may not be given of the fact that the estate meant to be sold was one situated at a different place and of a different size.