Behold, I have sinned. I have not worked all morning. My friend Susan is sitting huddled in Clapham fondly imagining I am busy writing half a book with her and in fact I am not writing half a book at all. I am busy making a cabinet. Two cabinets, actually. These cabinets are not specifically because I need cabinets; rather, they are because I am supposed to be writing Chapter 2 and in fact I suffer from a dreadful affliction which is to say whenever there is a pressing deadline (though can Chapter 2 be pressing?) I indulge in Workshop Tidying. This is an affliction specific to me. Nobody else in the world suffers from it. Faced with a difficult drawing I will spend two hours sharpening every pencil I possess and then I will hoover the room even under my glass draughting table and - mark this - behind the computer. Amazing how much fluff a computer generates. If the world abandoned computers there'd be a fluff shortage.

Faced with Chapter 2 I immediately note that the four drawers and broken cupboard that Dr Brewer didn't want and very kindly gave me have been sitting idle in the sheds for a month, so naturally now is the time to fetch out the glue and screws and saws and convert them into useful storage space for the lathe chucks which have been sitting bathed in unholy swarf these four years past on the floor where lathe chucks have no business to be, and I am not going to offer a photograph of the resultant cabinets because I happen to know for a fact that Nigel Farrell, whose exploits have been hitherto detailed here, is a cabinet maker and I don't want him laughing at me. His wife's called Annaliisa, by the way. One of us can't spell.

Anyway, my steel has arrived so I have few excuses to make cabinets and ought to be busy rebuilding Sam the Scotchman's trike frame as my chief displacement activity. (I call him a Scotchman because I happen to know for another fact that they hate being called that.)(Everyone knows that.)(Uh?)(So why did I tell you?) Unfortunately John is studying Balanced Forces so further work on trikes/cabinets/Chapter 2 has to be postponed while we deal with this, because harrassed schoolmistresses cannot explain Balanced Forces to thirty fourteen-year-olds in forty minutes with even the remotest chances of success. Luckily his memory of Mr Knight zooming round and round at 50 kph for an hour is fresh, so we focus on

a) how much air weighs (.88 kg per cubic metre, from memory)

b) how much of it you scoop up in your arms when you pedal through it

c) pedalling twice as fast means you scoop up twice the mass in the same time

d) and that you have to accelerate all that extra air not only to how fast you were going, but to how fast you are now going

e) if you can just nudge it aside, diagonally, instead of scooping it up in your arms, then you can go faster

f) which is what Bob's fairing was all about

g) and that when you start off your force isn't balanced which is why you accelerate

h) and that when your forces balance you stop accerating

i) which is why Bob couldn't go faster than 50 KPH.

This is a lot to take in, so we move onto what forces apply when a 22 year old stands on top of a car with his trousers round his ankles http://forums.gumtree.com/topic228071.html and the car suddenly stops. He has velocity, but no force. Accordingly he continues forwards at his constant 80 kph, until his face encounters a force. The force grinds his face off, and as he is not pedalling or running to perpetuate his velocity, he undergoes negative acceleration. John enjoys this greatly. Whenever the concept becomes difficult, we add lurid detail. It is a topic of considerable interest because it so happened that John and I were driving down to stay with Bob Knight on the morning this unfortunate incident took place, and were held up for half an hour at the Lewis Pass watching the rescue helicopter. The fireman told us 'not a pretty sight' but when we were allowed past John reported that he saw a body lying in the road but no crashed car, which mystery was only solved as the news reports came through. The 22-year-old gentleman concerned is now, I gather, on my mate's mechanical engineering course, where he exhibits a Police ankle bracelet, half a face, a surprising amount of conceit at his fame, and occasional absences for further reconstructive chirurgery.

My mate (in the Australian sense, not the animal pairing sense) is the Editor of the New Zealand HPV Newsletter, and further shares with Dr Lowing a misplaced enthusiasm for those front wheel drive bikes where the bottom bracket is allowed to waggle about along with the handlebars and front forks. He's just bought a lathe, and needs to know how to work it. My (Australian) mate that is, not old Lowing. Lowing needs to get on with his dissertation on Intellectual Law. And I need to get on with Chapter 2. And the mooning young man on top of the car needs to grow a new head, this time with a brain in it.