Oooh...Procul Harum alert. It's like that test you hear about, where you can tell you're middle-class if you hear The William Tell Overture and don't think immediately of The Lone Ranger.
This familiar tune is not entirely Bach at all but an adaptation of Bach's Air, part of his Orchestral Suite no 3 in D (BWV 1068) which he wrote for Prince Leopold in the early years of the eighteenth century. It was later adapted by the German violinist August Wilhelmj into the more familiar tune we all know.
This is one of those pieces of music that is evidently great but I really have no idea why. It just is. It moves along at a fairly reserved pace (my take is a little faster than some as it can sometimes seem to plod) and has a gracefulness of melody that seems to just start and move on without leaving the spot where it commenced. Once exhausted of all it can say on that fixed spot in space it just vanishes without a trace. Was it ever there in the first place? It also seems to occupy the same tonal centre throughout its duration, yet never deigns to repeat itself. At the very point where it seems that it is bound to repeat itself, the music stops.
The piece is scored for a string quartet but I found that it a little thin in places on the Mellotron, so I added much more into it and in the dubious process made it a great lumbering mass of rather mechanical sounding concrete and timber that was completely at odds with what I was trying to get across. So, I gave up on all of that and tried again, this time by revoicing it using what you see below, but playing much more subtly. Sometimes it's not transparent what the counterpoint behind the Classic Strings is doing, but the fact it is there is important.
Those of you interested in this tune may also like to hunt around for Antony Verbern's recording from the 1970s on the CRD label where it is played on a variety of different instruments including flutes, a 16th century pipe organ and a lute. Unfortunately I only have it on vinyl so I'm not able to give you links to handy Internet outlets, but it's maybe the best and most unusual version I have heard.
This is also available on YouTube.
Instrumentation: Mellotron M400 Playing