We sometimes dope this glass with other metal oxides to change the optical characteristics: thallium oxide is used in faceplates for deep sea divers and lanthanum oxide in camera lenses.
On day three, a troop of baboons go about their daily grooming and tick-picking tasks with nonchalance, ignoring both the camera-toting hikers and the dollops of yellow foam blowing off the angry sea.
The feed from a camera on board a salvage ship was discontinued Saturday after the apparatus was raised from the sea floor and placed on the vessel Q4000.