I'm looking for a teen book from roughly the 1960's starring two male friends about 11 to 13 years old. They are interested in science, a little bit like Danny Dunn and his friend Joe, without the evil genius aspect of The Mad Scientists' Club. The book is narrated in the first person, from the point of view of one of the boys.
They have all sorts of misadventures, but the only one I really remember is toward the beginning of the school year when they have to conduct an experiment that will demonstrate how it is possible to estimate the circumference of the earth by taking readings from two large hills that are a known distance from each other. The weather is unusually warm and humid for October, so their reading is off (it makes the one hill look like it is slightly away from where it actually is when viewed from the other hill). The boys check their calculations over and over, and can't find anything wrong: if the earth doesn't curve in the distance between the hills, it doesn't curve at all; it must be flat.
They are required to present their findings the next day at an assembly, conducted by the principal, in front of the whole school. The principal, who trusts them because of work they've done previously, proudly asks them on stage, "So, boys, what did you find?" They're trapped. They must tell the truth. One admits the horrible truth into the microphone, "We found out the earth is flat!"
Thunderous laughter shakes the auditorium. Every student in the school is laughing at them. The laughter goes on and on. It would start to die down, then it would erupt again. The principal is standing next to the boys with this ghastly frozen smile on his face. It's awful, but it is also one of the funniest moments in all of teen/tween fiction.
I can't for the life of me remember anything else about this book -- not the title, author, heroes' names, anything! Any help will be forever appreciated!
