DR. FOURNIER D'ALBE'S book is chiefly a history of the optophone, the instrument for enabling the blind to read ordinary print. This history claims about one-third of the volume and deals in ...

Selenium is a mineral that may support several aspects of human health. Most adults need around 55 micrograms (mcg) per day. Sources include nuts, eggs, and some fish. Selenium is a nutrient that ...

Selenium is a group 16 element with the atomic number 34. It is a metalloid and shares several of its properties with oxygen and sulfur, which are the most well-known members of this group. Jons Jakob ...