18. If upon the return of such warrant it shall appear that no sufficient distress can be had whereon to levy such penalty, and same shall not be forthwith paid, or in case it shall appear to the satisfaction of such Magistrate by the confession of the offender or otherwise that he has not sufficient goods and chattels whereupon such penalty could be levied if warrant of distress were issued, such Magistrate may, by warrant under his hand, commit the offender, to prison, there to be imprisoned, according to the discretion of such officer, for any term not exceeding two calendar months when the amount of penalty shall not exceed fifty taka, and for any term not exceeding four calendar months when the amount shall not exceed one hundred taka, and for any term not exceeding six calendar months in any other case, the commitment to be determinable in each of the cases aforesaid on payment of the amount.