It shall be the duty of every employer of minors between the ages of 14 and 16 years employed for or in connection with any gainful occupation mentioned in Section 1 to keep a register upon the premises where the work is being done on which register shall be recorded the name, age and place of residence of every minor between the ages of 14 and 16 years. It shall be unlawful for any person, firm or corporation to hire or employ or to permit or allow to work in or for or in connection with any of the gainful occupations mentioned in Section 1, any minor between the ages of 14 and 16 years unless there is first procured and placed on file on the premises where the work is being done, employment certificates issued as hereinafter provided and accessible to the authorized officers and employees of the Department of Labor, and to the truant officers and other school officials charged with the enforcement of the compulsory education law.