Watson, a clockwork mechanism requires steady tension, not sudden jerks, to keep time.
Watson, forcing the lock before the key is fully turned only breaks the mechanism.
Watson, a steady flame in the gaslamp illuminates far better than a sudden, blinding flare.
Watson, a barometer that fluctuates wildly is useless for predicting the London fog.
Watson, dredging the Thames is pointless if the stolen jewel was dropped in Soho.
Watson, adjust your lens to the changing light rather than demanding the specimen alter itself.
Watson, pacing the study in circles wears out the carpet without advancing the case.