Why there is no "the" in the second case? For me both of this cases look identical.

> His father gave him a bag full of nails. (...) On the first day he hammered in 37 nails, but getting **the(1)** nails into the fence was not
> easy. As the days went by, he was hammering in less nails, and within weeks he
> was able to refrain from getting angry
> and from hammering **<strike>the</strike>(2)** nails.