One can repeat the same experiments placing a thin pane of glass between the phosphorescent substance and the paper, which excludes the possibility of chemical action due to vapors which might emanate from the substance.
1564 - 1616
1803 – 1882
1854 – 1900
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1928 – 2014
1835 – 1910
1869 – 1948
1884 – 1962
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1809 – 1865