Chrystalline

Becauſe in the Conſpection of Objects remote, the Pupil of the Eye is expanded circularly, for the admiſſion of more Rays, and the Chryſtalline Humour ſomewhat retracted toward the Retina Tunica, for the Determination of the Point of Concurſe in the ſame, which otherwiſe would be ſomewhat too remote: and on the contrary, in the Conſpection of Objects vicine, the Pupil is contracted circularly, and the Chryſtalline Lens protruded ſomewhat outwardly, for the contrary reſpects.

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Hence Goëthe has ingeniously compared Shakspeare’s characters to watches with chrystalline plates and cases, which, while they point out the hours as correctly as other watches, enable us at the same time to perceive the inward springs whereby all this is accomplished.

Source: wiktionary

And lifting up to the chrystalline skies / Her eyes in tear o’erflowing sorrows drown’d, / All that she had to lift to heaven (her eyes) / Her hands by cruel Alguizils were bound.

Source: wiktionary