Provisional assessment allows payment of tax on provisional value or rate pending final determination, secured by bond. The statute allows a taxable person unable to determine value or tax rate to seek a provisional assessment, permitting provisional tax payment at a rate or value specified by the proper officer. Provisional payment requires execution of a prescribed bond with surety or security, securing payment of any difference between provisional and final tax. The proper officer must finalise assessment within six months, subject to limited extensions, and interest is payable on unpaid provisional tax from the original due date until actual payment; refunds following final assessment attract interest under the refund provisions.