Evidence for the first pure sample was presented in 1866 prepared by Hermes.

It would be very hard to find a pure sample of copper in a residential area.

A simulated pure sample has been found to be 58% harder than diamond.

Scientists have also succeeded in making pure enough samples of materials to begin studying their structure.

If possible, he is to obtain a pure sample of the original virus so a cure can be made.

A relatively pure sample of the metal was obtained only in 1953.

Before that, all 'gases' were considered to be more or less pure samples of air.

This group found that only 62% were definitely identified as a pure sample of the correct clones.

But scientists have never had pure samples to study.

Relatively pure samples of isolated elements are uncommon in nature.