One of THE greatest ever piece of vinyl, remember standing in a field in the 80's listening to chime roll accross the landscape? BLISS, Buy one! Always a great B*side too deep trance like on orig i do'nt know about FFRR ones though.
As behemoth says, it's the B which needs a listen if you've not heard it. Even at the time, obviously Chime was blowing up, but Deeper was the standout track. It just hangs together better and seems to signpost the way Orbital went with their developing sound better than Chime which was kind of a one-off. IMHO of course.
No need to mention the a-side - everyone knows that. But the b-side you might not be so familiar with. Orbital have always done excellent b-sides, and this is no exception. It's an acidic sizzler with excellent bleepy-bloopy noises. It has an amazing room-filling quality to it, and Orbital sampled one of their mother's relaxation tapes. The voice through tells you to "focus on my voice, and let every muscle in your body relax" - it may sound crap in writing, but it's a very trippy piece. When it finishes, you'll probably think "where am I?". Well worth tracking down, but it may come at a high price.