"A positive biaxial interference figure with the principal sections nearly corresponding to those of…
"A biaxial interference figure showing the emergence of an optic axis. The arrow indicates the movement…
"A negative biaxial interference figure. The arrows indicate the movement taking place upon inserting…
"A positive biaxial interference figure. The arrows indicate the movement taking place upon inserting…
"Movement of the left bar...upon rotating the stage to the right, and movement of the colored rings…
"A positive uniaxial interference figure. The arrows indicate the movement taking place upon inserting…