Preface: I've read this question about water preventing an initiation from occurring.
I understand why it's important to slowly add the alkyl halide to the dry ether and magnesium for exotherm control. But why is the first addition called an initiation and what's its purpose?
Is it just to confirm that the conditions are ready to continue slowly adding the rest of the reagent? I know it's a free-radical reaction, maybe that's where the term "initiation" comes from. But I've seen the reaction described as "self-sustaining" after the initiation, but it's not a chain reaction. Perhaps that's referring to a predictable reaction proceeding forward instead of stalling then blowing up your glassware.