Ich bin ja Herr, in deiner Macht

On of the last Kirnberger preludes I'm going to upload.
Interesting in the prelude on “Ich bin ja Herr in deiner Macht” is that the piece is written in A major and touches on f sharp minor and c sharp minor. Quite daring for the time. Perhaps the piece was meant as showcase (or testcase) for one of Kirnberger’s own tuning systems?

Score available here:
http://partitura.org/index.php/johann-philipp-kirnberger-ich-bin-ja-herr-deiner-macht/