Does it say why there are substitute teachers there during the summer?

Yes, it is a time of war so not only have younger men gone to war but they were not afforded the same services like cleaning and laundry.

Is there a particular page in the book that says the younger teachers have gone to war and that is why there are the substitute teachers?

I actually don't have the book in front of me, sorry.

alright I just have to make a comparison between John Knowles's life and his book and in his school life, the younger teachers leave for the war, leaving his class with older teachers causing distance and causing the students to be more independent, and in the book there are substitute teachers but i cant find a quote saying that the teachers left for the war so my comparison doesnt really work

I know that the author writes that he entered Exeter school in 1942 and found all the teachers were too old, tired or busy to relate to. The same goes for the novel but I don't have it here. Perhaps a Google search might help.