An isotherm is a line of equal or constant temperature on a graph, plot, or map; an isopleth of temperature. For example, isotherms are commonly seen on weather maps to show large-scale temperature distributions.
Drawing Contour Plots (http://avc.comm.nsdlib.org/cgi-bin/wiki_print.pl?Drawing_Contour_Plots). A lesson plan that deals with drawing various isopleths including isotherms.
... March 28 - Werner Bahlsen[?], biscuit[?] producer (+ 1985)
April 3 - Sally Rand[?], dancer (+ 1979)
April 7 - Ralph Bunche[?], diplomat, winner of the Nobel Peac ...