[Boatanchors] 19, 30 & 31 tube info

[LARRY D GODEK]

I have  a box full of 19, 30 and 31 type tubes.  Are they worth anything?  I suspect early 1900's radio sets may have used them.  My Hickok tube tester won't check them so i guess checking for fil continuety will be about the extent of testing.
 
>From a GE Essential Characteristics manual:
 
Type 19- Twin Triode Power Amp, 2.0 Vdc fil., 135 V plate
 
Type 30- Medium Mu- Triode, 2.0 Vdc Fil, 180Vdc max plate
 
Type 31- Power Amp Triode, 2.0 Vdc Fil., 180Vdc plate, .375W output
 
Larry
W0OGH