Clark and Van Til, Before the Controversy

For part of the biography I’m writing on Gordon Clark I’m researching into the relationship of Clark to his later philosophic adversary, Cornelius Van Til.
In 1936 (and perhaps in later years) Clark actually taught from Van Til’s material at Wheaton College. In prior years it seems they knew each other in Philadelphia and often had discussion on philosophy.
I’ve recently received four letters from the Orthodox Presbyterian Church archives between the two philosophers. Signs of the controversy still years away are evident in these letters. Clark, characteristically, critiques Van Til’s poor word definitions in a letter of August 28, 1937:
“You use the word knowledge in the Biblical sense of to know and love. Hence when someone objects that Paul says that the heathen know God, which seems to make possible a common ground, you reply that the heathen do not know God because they do not love him. Thus you avoid, not to say evade, the difficulties which arise from the consideration of what some call purely intellectual knowledge. But, may I ask ,when you say knowledge is knowledge and love, what does the second knowledge mean? Naturally, the definiendum cannot occur in the definition. How does this second knowledge occur? Within this strict sphere has the regenerate no common ground with the unregenerate? My impression is that you oscillate between love and that second knowledge to an extent which makes your simple word knowledge too ambiguous for exact usage.”
Later in this same letter Clark critiques Van Til’s “solution” the problem of the one and the many.  It seems that the archive is missing Van Til’s response.  Three extent letters are from Clark and only one from Van Til.