volverse oscuro

(v.) = turn + dark

Ex. For fifty years impregnated papers have been used which turn dark at every point where an electrical contact touches them by reason of the chemical change thus produced in a iodine compound included in the paper.

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(v.) = turn + dark

Ex: For fifty years impregnated papers have been used which turn dark at every point where an electrical contact touches them by reason of the chemical change thus produced in a iodine compound included in the paper.