That the said Maritime Canal Company shall not issue any bonds or mortgages. and shall not indorse or guarantee the paper. contract. or obligation of any person. persons. or corporation whatsoever. and no contract shall be entered Into or purchase made by said company. except for purposes provided for in this act. SEC. 13. That all sums expended in the purchase of material and supplies in and about the construction of said canal. including dredging machinery and ships. shall be purchased in the United States. except such material and supplies as may he grown or produced in Nicaragua or Costa Rica. or not grown or produced in this country. and no Asiatic labor shall ever be used or employed in the construction of said canal. SEC. 14. That no dividends shall be declared by said Maritime Canal Company except from the net earnings of said canal.