Section 4. Paragraph (a) of Section thirteen of the same Act is hereby amended to read as follows:

"Sec. 13. Definition of terms. — (a) Mechanical engineering. — A person shall be deemed to be practicing mechanical engineering or rendering mechanical engineering service within the meaning and intent of this Act, who shall, for a fee, salary or other reward or compensation paid to himself or to another person, or even without such reward or compensation, render professional mechanical engineering service in the form of consultation, investigation, valuation, planning, design, or preparation of specifications or estimates for, or take charge of management, administration and supervision of the construction, erection, installation or alteration of, or render engineering service in connection with the manufacture, sale, supply or distribution of, or to manage, operate, tend or maintain any mechanical equipment machinery or process, for any mechanical works, project or plant; or who shall, by means of signs, cards, advertisement or in any other way, offer to practice mechanical engineering or to render professional mechanical engineering service, or who shall in connection with his name, or otherwise, use, assume or advertise any title or description tending to convey the impression that he is a professional mechanical engineer, or mechanical engineer, or certified plant mechanic, or that he is engaged in the practice of mechanical engineering as defined in this Act."