Hi, Marshall, Yes, a laser pointer and the use of Snell's law can give a calculation of refractive index. But the principle of the optical lever would allow more precision. Admittedly, not everybody has access to a theodolite or a transit. These instruments, used as part of an optical lever setup, could provide both precision and accuracy. The latter would come from the capability to "close" the "survey" by turning the instrument to view the graduation with and without the refracted path. A method of comparable precision, though maybe not quite as much accuracy, and much more feasible for people of ordinary means, would be to use telescopic gunsight instead of theodolite or transit.
Best regards, Matthew
