Capital stock of a stock company formed under this act shall not be less than twenty-five thousand dollars, and shall be divided into shares of not less than ten dollars each, payment of which shall be made in lawful money, ten per centum on each share at the time of subscribing, and the balance at such times as the company may direct, not exceeding one year from the time of subscription; and the company may provide such rules with regard to forfeiture of partial payments on subscriptions as they may deem advisable, which rule shall be binding upon the subscribers, provided they are made known at the time of subscription. Each such company shall, in addition thereto, have a surplus paid in at least equal to the amount of the capital stock.