var imageFiles_4oc_1 = new Array();
imageFiles_4oc_1['0'] = new Array ('_images/4oc_Back_to_Isaac_Newton_Pg_1.gif', '_images/4oc_Back_to_Isaac_Newton_Pg_1Mouseover.gif');

function image_on_4oc_1 (position) {
   var doc = eval("document.image4oc_1" + position);
   doc.src = imageFiles_4oc_1[position][1];
}

function image_off_4oc_1 (position) {
   var doc = eval("document.image4oc_1" + position);
   doc.src = imageFiles_4oc_1[position][0];
}