Provided also, that every proprietor of an entailed estate, who intends to lay out money on such improvements, shall, three months at least before he begins to execute the same, give notice in writing to the heir of entail next entitled to succeed to the said estate after the heirs of the body of the said proprietor, if within Great Britain or Ireland, and if the heir next entitled to succeed is not within Great Britain or Ireland, shall give notice in writing to the nearest male relation by his father of lawful age, or to his known factor or attorney, of such his intention, specifying in such notice the kind of improvement intended, and the farms or parts of the estate upon which the improvements are intended to be made; and shall lodge a copy thereof with the sheriff or steward clerk of the county wherein the lands lie.