Looking for an accepted grammatical explanation.

The pull of gravity becomes less the farther you move away from Earth’s center.

In the above sentence it is not clear to me what other role 'the farther' plays besides its role as an adverb. Although it is not difficult to understand what the sentence implies, I want to know if the usage of  ' the farther' in this sentence is a well-known grammatical construction.

The farther you move away from Earth's center, the less the pull of gravity becomes.

I am very much familiar with this 'contrasted comparatives' or 'combined comparatives' construction.

Your input will be greatly appreciated.

Peano wrote:

The sentence is grammatically correct, but I think it could be improved by switching the order of the clauses (so that cause precedes effect): The farther [away] you move from the Earth's center, the less the pull of gravity becomes. Having made that switch, I would think about variations: As you move farther from the Earth's center, the pull of gravity decreases.

I am afraid that you did not add anything to what I had already stated.

Peano wrote:

You asked whether "the farther" in that sentence is a well-known grammatical construction. When I replied that the sentence is grammatically correct, that was intended as a "yes" answer to your question. What there something more you were asking?

You did not explain what role this 'grammatically correct' phrase play in conneting the two clauses. I do not see any obvious conjuction. That was the crux of my question.

"The farther you move away from Earth's center, the less the pull of gravity becomes"

This "the" was originally "thy", i.e., the instrumental case of the nominative definite article "the" and was used to mean "by means of". Now this "the" is lexically classed as an adverb and OED's grammarians take it that the first "the" means "by how much" and the second "the" means "by so much"
       "By how much farther you move away from Earth's center, by so much less the pull of gravity becomes."
The oldest use of this construct appeared in King Alfred's translation of Gregory's Regula Pastorialis scripted in 897: "Ðæt her ðy mara wisdom on londe wære, ðy we ma geðeoda cuðon"

On the other hand, a British grammarian Quirk explains "the … the …" in his CGEL as paring subordinators to make up a proportional relative clause similar to "as … so …".
       "As you move away from Earth's center farther, so the pull of gravity become less."
Suppose the paired "the"s could be used independently, and suppose
       The pull of gravity becomes less the farther you move away from Earth's center.
be grammatical, then it would be paraphrased like:
       "As you move away from Earth's center farther, the pull of gravity become less."
It makes sense, but sounds somewhat weaker in the sense of proportionality than "the ... the …" or "as … so …"

paco

Peano wrote:

I think this answers your question: Farther and less are simply adverbs; the two clauses are linked by the … the …, which function as correlative conjunctions comparable to such pairs as either/or, neither/nor, etc. Take a look here (search the page for "correlative conjunction" -- it's pretty far down): http://grammar.ccc.commnet.edu/grammar/grammarlogs4/grammarlogs502.htm"

If you go back and review what I said in my original question, you will know I said I already knew about the "correlative conjuction". But the sentence in question is not in the same form or construction.