My own reading of it is that it was a clever evasion of his son-in-law's attempts to make sure of his share of the inheritance.

We have seen how shifty Defoe was in the original bargaining about his daughter's portion, and we know from his novels what his views were about fortune-hunters, and with what delight he dwelt upon the arts of outwitting them.

He probably considered that his youngest daughter was sufficiently provided for by her marriage, and he had set his heart upon making provision for her unmarried sisters.

The letter seems to me to be evidence, not so much of fears for their future welfare, as of a resolution to leave them as much as he could.

Two little circumstances seem to show that, in spite of his professions of affection, there was a coolness between Defoe and his son-in-law.