program data_reader
      real time(100),Temp_black(100),Temp_white(100)
      open(unit=10,file='cooling_data.txt')
      read(10,*)n
      do i=1,n
        read(10,*) time(i),Temp_black(i),Temp_white(i)
      end do
      close(10)
      if(pgopen('/xwin')<=0)stop
      call pgenv(time(1),time(n),20.0,100.0,0,0)
      call pgpt(n,time,Temp_black,9)
      call pgclos
      end