3. It shall be the duty of the county assessor to enter such statements in a book to be prepared for that purpose at the expense of the county, suitably ruled, with columns for the name of the merchant, the amount of his or their statements as returned to the assessor, the valuation of such statements as equalized by the county board of equalization, and for state, county and school taxes, and such other columns as may be found useful or convenient in practice; such book shall be verified by the affidavit of the assessor, annexed thereto, in the following words, to wit: "______, being duly sworn, makes oath and says that he has made diligent efforts to secure sworn statements from all persons, corporations or firms doing business as merchants in the county of which he is assessor; that so far as he has been able to secure such statements they are correctly set forth in the foregoing book."