. . "of himself, or of himself and Henry M. Wheeler, for the sum of least $10,000, and assign the same to him, Reed, as collateral security to the said last bond and mortgage, and would annually renew the policy, or effect a new one, and keep each assigned to Reed as security, in such way and manner as that the said property shall be insured for at least the sum of $10,000, and the policy held by him a" . .