| Zircon also has very pronounced birefringence or double refractivity, where the difference between the two refractive indices is unusually high. |
| Steam treatment of tissue sections in citrate buffer at pH 6.0 did not increase the polariscopic refractivity of the organism. |
| In air and other gases, at ordinary pressures, the dispersion is very small, because the refractivity is small. |
| In order to do this, it was necessary to agree the relevant propagation zone type and refractivity gradients for the applicable time percentages. |
| In this case small temperature changes alter the refractivity of the liquid without appreciably affecting the quartz. |
| Glasses can now be made differing considerably both in refractivity and dispersive power. |
