Crookes Tube

The Crookes tube was named after the British chemist and physicist Sir William Crookes (1832-1919).  The Crookes tube is the predecessor of the cathode ray tube that made television possible though its primary use is as a classroom demonstration device.  Like most items of this sort, it was made in Germany.  There is no way to establish a date, but it is probable that it was made in the early part of the 20th century.  It is about 10 inches long, and 4 inches in diameter at the widest point.

The interior of the tube is evacuated, and when a sufficiently high voltage is applied, a stream of electrons travel from the cathode (the small end) toward the anode (at the center bottom of the tube). 
Those electrons that miss the anode travel towards the large end of the tube and cause the residual gas inside the tube to fluoresce.  The aluminum Maltese Cross serves to block the flow of electrons and creates a dark pattern on the inside of the tube.