¹* * * In the event of such increase, the Proprietors of the original Stock shall not be bound to subscribe, but shall in the first instance have the option of subscribing for the increased Capital Stock in proportion to the share which each has of the original Capital Stock; and so much of the additional Capital Stock as shall not be subscribed for by the said Proprietors of the original stock, within one year after the passing of the final resolution for the increase, shall be open to the public, and be sold, for the benefit of the said Association, by public sale.