...those by whose acts he is bound, has acquiesced. Declarations or conduct which might not of themselves amount to an estoppel may become such by acquiescence. Estoppel by acquiescence is, obviously, closely related on the one hand to estoppel by consent, and, on the other hand, to estoppel by silence or inaction, or...involve anything in the nature of a positive affirmation; and while, as has already been pointed out, silence or inaction may, under some circumstances, amount to acquiescence, it does so only where...silence, or that the payment of taxes by the McQueens on this property after the death of the life tenant in 1939 was not a change of position by the McQueens in reliance upon the conduct of Mrs...