If you ever find yourself in a situation where you’ll need a smooth horizontal scroll for both, a good old mousewheel and a trackpad (iPad, MacBook etc.), there is a good plugin, called ‘mousewheel’.
It’s setup, however, can be rather tricky. I ended up a few times having my scroll items bounce wildly around, stutter or jump on initial hit.
The piece of code you’ll find upon hitting this link solves all of those problems in just one line of code!