function sectionFadeIn() {
$('.fadein').each(function() {
    var top_of_object = $(this).offset().top + 50;
    var bottom_of_window = $(window).scrollTop() + $(window).height();
    if (bottom_of_window > top_of_object) {
        $(this).animate({ 'opacity': '1'}, 1000);
     }
})

.fadein {
    opacity: 0;
  }

  .fadein:first-of-type {
    opacity: 1;
  }