Section 19A. The justices of the superior court may appoint for a term of five years, and may at any time for cause remove, a special master, who shall receive from the commonwealth a salary of five thousand dollars. He shall perform such administrative duties pertaining to the court and shall hear and dispose of such interlocutory matters relating to the assignment, postponement, continuance and order of trial of cases, at such times and places as the chief justice of said court may determine. Every order or decision of said master shall be subject to appeal to the court and the appellant shall be granted an immediate hearing.