Other mistake: Throughout the episode, including the very first shot, we see the sun is shining brighter and hotter than usual. This lends credibility to the theory that Superman's powers are responsible for increased solar activity. Later on in the episode it is revealed that the heatwave is being orchestrated by Lex Luthor, who is is heating an underground river to coincide with Superman using his powers. Lex does not however have any control of the weather, and no explanation is offered for why the weather conveniently 'played along' with his plan.
Lois & Clark: The New Adventures of Superman (1993)
Episode list - season 3
Starring: Teri Hatcher, Dean Cain, Lane Smith, K Callan
More mistakes in Lois & Clark: The New Adventures of Superman
Superman: But, when I save a life, in that instant, I know two things that most people will never figure out: Why I'm here, and how I can make a difference.
Brutal Youth - S4-E5
Trivia: Jack Larson, who played Jimmy Olsen in "The Adventures of Superman" in the 50s, portrays Jimmy Olsen as an old man.
Question: Whenever Clark uses his X-ray vision, why does he lower his glasses? Lowering them when he uses heat vision is understandable but there's no need to do it when Clark uses X-ray vision.
Answer: I don't recall if it was ever mentioned in an episode, but it's possible that the frames and/or lenses of his glasses are lined with lead, the one compound his X-ray vision can't penetrate. Speculative, of course, but it likely would have been done at a point in his youth when he wasn't in complete control of his powers.
Cubs Fan ★
I think the other answer has good speculation. I would add it could also just be an "acting gesture" that Dean Cain utilizes as part of his Superman character and not because there's any practical reason. That way, the audience immediately recognizes what he is doing.
raywest ★