diff --git a/src/viewport.js b/src/viewport.js
index d37bfbae..853458df 100644
--- a/src/viewport.js
+++ b/src/viewport.js
@@ -143,7 +143,7 @@ $.Viewport = function( options ) {
     this._oldCenterX = this.centerSpringX.current.value;
     this._oldCenterY = this.centerSpringY.current.value;
     this._oldZoom    = this.zoomSpring.current.value;
-    this._oldDegree  = this.degreesSpring.current.value;
+    this._oldDegrees  = this.degreesSpring.current.value;
 
     this._setContentBounds(new $.Rect(0, 0, 1, 1), 1);
 
@@ -1006,13 +1006,13 @@ $.Viewport.prototype = {
         var changed = this.centerSpringX.current.value !== this._oldCenterX ||
             this.centerSpringY.current.value !== this._oldCenterY ||
             this.zoomSpring.current.value !== this._oldZoom ||
-            this.degreesSpring.current.value !== this._oldDegree;
+            this.degreesSpring.current.value !== this._oldDegrees;
 
 
         this._oldCenterX = this.centerSpringX.current.value;
         this._oldCenterY = this.centerSpringY.current.value;
         this._oldZoom    = this.zoomSpring.current.value;
-        this._oldDegree  = this.degreesSpring.current.value;
+        this._oldDegrees  = this.degreesSpring.current.value;
 
         return changed;
     },