know at home as 'spiritual life.' There are some fine fellows here and some high ambitions, but the chapel service is all voluntary, and only a handful of fellows ever go unless some big gun comes to give a chapel talk, and then the president allows only fifteen minutes for the whole service. "What you wrote about Helen having a beau was funny. I can't imagine what Helen will do when the callers begin to come. Well, mother, I want you to think of me as too busy with my work to get into any more trouble. I am awfully interested, especially in the original problem--I believe I almost stumbled on the making of a successful arc light, without a regulating mechanism, a few days ago. I have been dreaming over it ever since and I am quite confident it can be done. Felix Bauer said the other day he thought he had it all right, but the plan escaped him. It's exciting, mother, to keep trying different combinations, not knowing any minute when you may hit on a new discovery. I hope Louis is behaving himself in his studies. I am sending him by mail a time switch that he asked me about. "Much love to all. Your affectionate son "WALTER." Esther read this letter over carefully twice, and then, as her habit was, answered it almost immediately. It was a part of her training of her children that she had frankly taken them into her confidence when they were little and had had the wisdom and courage to discuss with them the questions that were really vital to their bodies and minds. There was one reason Walter wrote as frankly to his mother as he did about everything, knowing she would understand exactly. And that was the reason his mother in her turn could write as she did in reply, entering fully into the boy's real life.