GEOTHERMOMETER.FOR requires 4k (hex 1000) of stack space to run. 
Microsoft FORTRAN 5.0 has a default stack size of 2k.  If compiled
under this default setting, GEOTHERMOMETER will probably lock up
your PC quite effectively.  The enclosed executable GEOT_PC.EXE
was compiled from a copy of GEOTHERMOMETER.FOR with the command line:

fl /F 1000 geot_pc.for

It has been tested on a Zenith 386SX and seems to operate properly.
Good luck.

Victor Kress
11/4/92