Can the glass on a tube be repaired???

No. It is a "vacuum tube". Without the vacuum the tube is destroyed.

Maybe if it's rare enough might be worth searching for this guy:

http://news.cnet.com/8301-13645_3-9843011-47.html

What GMC and Narrod posted is correct, the tube is destroyed unless the glass can be remade and vacuum restored. Unless the tube is so rare it merits that I would keep it as a conversation piece or throw it away.

1.No
2.See #1.

What do you mean by "the top of the glass"?? If it is the external glass "point" on the top of the tube then the vacuum may be intact. If the glass body of the tube is cracked or broken then the tube will not work.

Thanks for the replies. The top of the tube, the glass is broken so you can put you little finger into it. Yeah rare 6SN7 tube go figure it would be the one that fell.