The qualifications for certification of a candidate for the office of mine inspector shall be as follows: The candidate shall be a citizen of the Commonwealth of Pennsylvania, of temperate habits, of good repute as a man of personal integrity, in good physical condition, shall be between the ages of thirty and fifty-five years, shall have successfully passed the examination for mine inspector provided in section 109 hereof,¹ shall have had at least ten years' practical experience in anthracite coal mines, five years of which shall have been immediately preceding the examination, and shall have had practical experience with explosive gas and other dangerous and noxious gases found in coal mines: Provided, however, That any candidate who has honorably served in the armed forces of the United States or any ally thereof shall be eligible to take such examination, where the required continuity of practical experience has been interrupted by such military service.