Once the lay-out of New York has been mastered - its avenues and numbered cross streets - it is the most difficult city in the world in which to lose one's way. But Boston is different. I found Boston hard to learn, although it was a pleasant task to acquire knowledge, for I was led into some of the quietest little Georgian streets I have ever been in, steep though some of them were, and along one of the fairest of green walks - that between the back of Beacon Street and the placid Charles.