The person producing an invoice for certification shall at the same time declare to the consul or vice consul the port in the United States at which it is intended to make entry of merchandise; whereupon the consul, or vice consul, shall indorse upon each of the triplicates a certificate, under his hand and official seal, stating that the invoice has been produced to him, with the date of such production, and the name of the person by whom the same was produced, and the port in the United States at which it shall be the declared intention to make entry of the merchandise therein mentioned.

No consular officer of the United States shall grant a certificate for merchandise shipped from countries adjacent to the United States, which have passed a consulate after purchase for shipment.

All consular officers are authorized to require, before certifying any invoice, satisfactory evidence, either by the oath of the person presenting such invoices or otherwise, that such invoices are correct and true. In the exercise of the discretion hereby given, the consular officers shall be governed by such general or special regulations or instructions as may from time to time be established or given by the Secretary of State.

All consuls of the United States having any knowledge or belief of any case or practice of any person who obtains verification of any invoice whereby the revenue of the United States is or may be defrauded, shall report the facts to the appropriate customs officer of the port where the revenue is or may be defrauded, or to the Secretary of the Treasury.

For the purpose of estimating the duties on importations of grain, the number of bushels shall be ascertained by weight, instead of by measuring; and sixty pounds of wheat, fifty-six pounds of corn, fifty-six pounds of rye, forty-eight pounds of barley, thirty-two pounds of oats, sixty pounds of peas, and forty-two pounds of buckwheat, avoirdupois weight, shall respectively be estimated as a bush