Section 9A. The salaries of the clerks of the housing court department appointed under the provisions of section nine shall be 81.57 per cent of the salary of the chief justice of said department and shall be paid, subject to appropriation, by the commonwealth. The salaries of the first assistant clerks in said department shall be eighty-three and one-half percent of the salary of the clerks of said court and shall be paid, subject to appropriation, by the commonwealth. The salaries of assistant clerks in said department appointed under the provisions of section eleven shall be seventy-seven percent of said clerk's salary and shall be paid, subject to appropriation, by the commonwealth.
Said clerks and assistant clerks shall devote their entire time during business hours to their respective duties and shall not, directly or indirectly, engage in the practice of law.