Every person engaged in the business of selling or soliciting orders for the sale or purchase of mimeographs, duplicating machines, dictaphones, teletypes, or other similar machines, and except any person regularly employed by a said agent of or dealer in which said agent of or dealer in has paid the privilege tax or license tax herein provided for, the following annual privilege tax shall be levied and collected: In counties of over 100,000 inhabitants, $30; in counties of over 60,000 inhabitants and not exceeding 100,000 inhabitants, $20; in counties of over 40,000 inhabitants and not exceeding 60,000 inhabitants, $15; and in counties of 40,000 inhabitants and less, $10. Such license shall not authorize such agent or dealer to do business in any other county than that in which the license is issued, but if such agent or dealer shall do business in any other county than that in which he has secured the license above provided, he shall pay an additional license in each such county where he solicits business of one fourth of the above enumerated amounts.