Da you are nitpicking without reason.
Everbody knows that light speed will vary under circumstances wherein the light passes through some medium or other. I specifically stated that the speed of light in a vacuum was measured at 186,281 miles per second, that is the vacuum of space in the solar system near earth. It has been so measured by NASA ans some smart fellows a long time age.
http://itotd/com/articles/284/ "Meanwhile, Foucault was working on a different but equally clever technique, which he demonstrated the following year. Foucault?s method was to shine a sharply focused beam of light onto a rotating mirror, and from there onto a fixed mirror. Once the light hit the fixed mirror, it bounced back onto the rotating mirror and then back toward the source. But because the mirror was rotating, the angle at which it was positioned had changed slightly by the time the beam made its return trip. Consequently, the reflected beam did not line up precisely with the original. Foucault could easily measure the angle between the original light source and the reflected beam, and along with known constants (the distances between the various surfaces and the speed of the mirror?s rotation), it was a matter of a few straightforward calculations to convert that small angle into a representation of speed. Using this technique, Foucault produced a measurement of 298,000 km/second (185,167 miles/second), which is shockingly close to the modern measurement of 299,792 km/second (186,282 miles/second), keeping in mind that the latter figure applies only in a vacuum; light travels more slowly in air."
I guess you have a measurement of your own creation and that is OK too, keep it secret.
jjw
