Related Clues:

• Volunteers
• Signs up
• Increases
• Accelerates
• Calls upon
• Increases, as production
• Registers
• Is promoted
• Joins the military
• Increases by degrees
• Joins up
• Signs on
• If one listens to the bits of this one joins forces with them
• Joins up so as to be silent about the South
• One will be 10 across if one does this