I agree with Barbara if the new cat is a kitten then this is normal. The kitten is just testing out it's abilities. I also agree that you may want to let your older cat take care of the situation.

You can help out a little bit by playing with the kitty and working off some of it's excess energy. You will never get rid of all of the excess energy. However, if the kitten finds other items to stalk or play with, it may do it less to the older cat. I am not saying that you don't already play with the kitten, but the more that you do the more energy will be worked off. It won't stop it completely, but it may lessen the frequency of the event.

I am not going from experience here, I have not had a kitten in a long time. I actually read that somewhere on the net, and it made sense to me.

Good luck.