It's interesting how its adhesive properties were discovered.
They were testing its refractive index.
The device used consists of a pair of glass prisims with a sample of the material in question between them. A beam of light shines through one of the prisms and the prisms are rotated so it strikes the prism/sample interface at various angles, starting with a very glancing angle. If the refractive index of the sample is sufficiently less than that of the prism, the light beam will experience total internal reflection, because penetrating the interface would bend it MORE than parallel to the surface, so it can't propagate away.
As the angle between the light and the surface increases it eventually reaches and passes the angle where the light would emerge and run parallel to the surface and continues with angles where the light would leave the prism at some angle and penertate the sample. The transition is very abrupt.
If the sample is transparent the light passes through it into the second prisim (and the degree of transparency can also be measured.) If the sample is opaque the light penetrates and is absorbed. (This is how you measure things like the refractive index of ketchup.) In either case the reflection of the light stops abruptly at some angle, and this angle gives you the refractive index (relative to that of the glass of the prisim).
So they tested it in this very expensive precision instrument.
Then they tried to get the prisms apart to clean them for the next experiment...
