Tone is defined as a writer's attitude, or feelings, toward the subject matter or even toward the writer's audience. Tone can be conveyed through a writer's diction and other literary devices (Literary Devices, "Tone").
In the short story "Through the Tunnel," author Doris Lessing's tone closely matches the feelings of the protagonist named Jerry. The tone is neither judgmental nor critical but is rather fully empathetic of the character's situation and needs and even jubilant.
Early in the story, Lessing shows that she fully empathizes with Jerry's conflict. She portrays that, on the one hand, since Jerry is the only remaining male in the household, though he is young, he feels a sense of duty to his mother. The author expresses empathy with Jerry's sense of duty when she uses the word "contrition" to describe his deep sense of remorse for having wanted to stray from his mother, as seen in the sentence, "Contrition sent him running after her." Lessing even describes him as chivalrous for wanting to uphold his duties.
Yet, on the other hand, throughout the story, the author also portrays Jerry's need to part from his mother to seek adventure. His need for adventure is captured in the description of the rocky bay as a "wild-looking place," which the author juxtaposes with the "safe beach." Yet, though it looks wild, the author also shows that Jerry is relatively safe in the bay since he is a strong swimmer. Lessing's juxtaposition of the wild looks of the bay with Jerry's relative safety help capture the author's tone of empathetic approval of Jerry's decisions and eventual jubilation, showing a very non-judgmental and empathetic tone.
Empathetic approval is also captured in the fact that, though Jerry causes his nose to bleed severely, which is a fairly minor injury, he is successful in his undertakings. He learns to hold his breath to the extent that the older boys do, and he manages to swim through the rock. He is even very sensible in his undertakings, as shown in the fact that he very carefully takes the time to train himself. Lessing shows he knows what he wants to achieve is life-threatening and, therefore, will not foolishly rush into the venture as other boys might. Since he so carefully and wisely teaches himself to undertake a difficult, even life-threatening task and succeeds, we can sense the author's tone is jubilant right along with her character's mood.