In a famous paper

Hartshorne - Varieties of small codimension,

Hartshorne formulates a conjecture, which roughly says that varieties of small codimension in projective space are complete intersections.

On page 1023, he mentions a positive result which he has proved on this conjecture, which uses the Chebotarev density theorem (!). It says that this result is to appear in a paper

Hartshorne - Projective varieties of small degree.

I'm having difficulty finding this paper. Did it ever appear in print? Have similar results been proved elsewhere using the same/different methods? As a number theorist, the use of the Chebotarev density theorem here greatly interests me, and I would be interested in seeing the proof with this method if it exists.