Newton's Purr - a sound similar to that of a diesel engine

Newton, my faithful cat of 15 years, is leaning up against me as I type. My loyal, ever-present friend with the big soulful eyes. He is always there, when I wake in the night he is across the top of my pillow. When I eat dinner he is at the right of my dish. When I work out in the yard he follows me closely. When I tell him it is time to come in for the night, he meow-purrs as he picks himself up and comes to the sound of my voice. When watching TV he lays on my chest. He paternally will hold down my hand with one paw and lick it clean, because he knows I need it, even if I disagree. He has been with me through a room-mate, a boyfriend, a husband, four different domiciles and a cadre of other animals. He has been sick and had to go to the emergency room, he has been lost so I had to search for him, he has been in fights causing me to run out into the yard screaming hysterically at local tom cats. He's travelled in my lap on long car trips. He has soiled and ruined many a throw rug. When we had two litters of kittens he became Uncle to all and taught them about good manners. He has even taught two puppies what is and what is not acceptable behavior. He has taught me that best friends let you live your life, forgive you when you forget about them, and still accept you with love when you are ready to notice them again, letting you pick right up where you left off.