In Chrome, select the Customize and Control
menu button and select Settings
Select Show Advanced Settings at the bottom of the page.
Select Content settings...
under the Privacy heading.
Select the All cookies and site data...
In the search box, type g-wonlinetextbooks
One or two instances should display. For all that display, select the item, then select para-zoomFactor
Repeat for the second instance if necessary.
Select Done twice to return to the settings menu.
Re-launch Chrome and access G-W Online Textbooks. The zoom feature should now work.