All known samples of N. nitida were from three collections taken between 1862 and 1864.

"The known sample came from a haircut three weeks before the murder," Bartholemew said.

No two hypocephali are the same, and there are just over 100 known samples of them.

So far, we couldn't even say very much about the known sample, the Borawash soap we used in the building.

Similarly, the patterns of the circular chromatographs can be "read" based on known samples.

No known samples were ever produced for military use.

One such method is interpolation or extrapolation of known samples.

Crookes identified the first known sample of helium, in 1895.

Unknowns that generate a stronger signal than the known sample are "positive."

Today, no known samples of the mysterious material exists.