ptural quotations and biblical diagrams as part of their theoretical correspondence. Perhaps the greatest mathematician of the 18" Century (or ever), Euler, in his Letters to a German Princess, discussed the functional characteristics of spirits and tt the connections between body and soul. Bell said E

We are also fairly sure we can form any number by adding two primes together. This is Goldbach’s Conjecture, set as a question in a letter written to Euler in 1742. It is still unproven! Euclid proved there are an infinite number of primes by using reductio ad absurdum. Imagine we have a complete list o