diff --git a/src/chart.zoom.js b/src/chart.zoom.js
index e7fd0867..9b8a7736 100644
--- a/src/chart.zoom.js
+++ b/src/chart.zoom.js
@@ -11,7 +11,7 @@ var helpers = Chart.helpers;
 var zoomNS = Chart.Zoom = Chart.Zoom || {};
 
 // Where we store functions to handle different scale types
-var zoomFunctions = zoomNS.zoomFunctions = zoomNSzoomFunctions || {};
+var zoomFunctions = zoomNS.zoomFunctions = zoomNS.zoomFunctions || {};
 var panFunctions = zoomNS.panFunctions = zoomNS.panFunctions || {}; 
 
 // Default options if none are provided
@@ -181,7 +181,7 @@ var zoomPlugin = {
 		var panThreshold = helpers.getValueOrDefault(options.pan ? options.pan.threshold : undefined, zoomNS.defaults.pan.threshold);
 
 		var wheelHandler = function(e) {
-			if (e.deltaY > 0) {
+			if (e.deltaY < 0) {
 				doZoom(chartInstance, 1.1);
 			} else {
 				doZoom(chartInstance, 0.909);