What is the duty of a trial judge to question witnesses from the bench?

"The duty of a trial judge, particularly in criminal cases, is more than that of an umpire; and though his power to examine the witnesses should be exercised with discretion and in such a way as not to prejudice the rights of the prosecution or the accused, still he is not compelled to sit quietly by and see one wrongfully acquitted or unjustly punished when a few questions asked from the bench might elicit the truth. It is his primary duty to see that justice is done both to the accused and to the people. He is, moreover, in a better position than the reviewing court to know when the circumstances warrant or require the interrogation of witnesses from the bench." (People v. Golsh (1923) 63 Cal.App. 609, 614-615, 219 P. 456.)