Index: Proj.js
===================================================================
--- Proj.js	(revision 2952)
+++ Proj.js	(working copy)
@@ -964,7 +964,7 @@
 	this.false_northing = param[4];
 	this.false_easting = param[5];
 	this.temp = this.r_minor / this.r_major;
-	this.es=1.0 - Math.sqrt(this.temp);
+	this.es=1.0 - (this.temp * this.temp);
 	this.e = Math.sqrt( this.es );
 	this.m1 = Math.cos(this.lat_origin) / (Math.sqrt( 1.0 - this.es * Math.sin(this.lat_origin) * Math.sin(this.lat_origin)));