| abstract |
The present invention pertains to the measurement of the refractive index of a medium, such as a fluid, through the wall of its container. The essential characteristic of the invention is that, by using at least two separate light paths that are of unequal length and that reflect from the wall/medium interface, it is possible to perform the measurement of the refractive index of the medium so that the result is insensitive to the color and thickness of the wall. |