	(STRING ADVERB of length 16 characters)

	XTITLE and YTITLE are used to label the x and y axis labels of
	the output of the PLOT verb.  XTITLE is the x label and YTITLE
	is the y label.

	XTITLE and YTITLE are used by :    PLOT     

	No verbs change XTITLE and YTITLE

	The initial values of XTITLE and YTITLE are blanks.

 	EXAMPLE :

 	To set the x-axis label of PLOT to "elevation" and the y-axis to
	"System Temp", specify;

		XTITLE = 'elevation'
		YTITLE = 'System Temp.'
