Re: i got trapped in Wales because

Whiskers <catwheezel@xxxxxxxxxxxxx> wrote:

Rowland McDonnell <real-address-in-sig@xxxxxxxxxxxxxxx> wrote:
Whiskers <catwheezel@xxxxxxxxxxxxx> wrote:

[...]

I don't know about 'plenty of' flint knappers; there are certainly some
who can do it, but not a great many. I'm sure they are greatly outnumbered
by black-smiths, for example.

I'm not. There might not be that many really good flint knappers, but
you'd be surprised. It takes less equipment to get started, at least.

Less equipment, certainly. Just catch, kill, and skin, a deer, cure the
skin to make leather for the padding your thigh will need,

Phooey. Mud (binder) and sticks and leaves will do, if you've got
nothing else.

and fashion a
shoulder-bone into a suitable tool for puttimg the pressure in the right
spot.

It'd do-able with rocks alone, for some jobs. Or you can use wood as a
hammer - if you can find a suitable bit.

Then all you need to do is find some flints of the right sort.

Which is actually quite easy if you're in the right part of the country.

- and it would be silly to ignore
all the metal lying around.

True, but how are you going to use it? You want to melt steel? You
need pretty high temperatures. Aluminium? Forget it: you need an inert
atmosphere. Oh, it'll be used, will the scrap metal, but it might not
be the best approach for everything and it'll certainly be in high
demand, will the scrap if it *is* useful.

Getting enough heat to melt iron isn't a huge problem, especially if you're
working small pieces and have raw metal to start with.

Not a /huge/ problem, but you're not going to do it without decent fuel
(charcoal might be all you can get, and making the stuff is a job that
most people haven't a clue about. I can do it), and some sort of
assisted-ventilation `stove'. There are a lot of pieces to put
together.

Bush blacksmiths seem to manage pretty well.

I've not seen how they do it, but it can't be *that* straightforward. I
still like the idea of stone tools.

Aluminium is
difficult to weld, but it takes well to casting and rivetting

You still need that inert atmosphere for casting the stuff - if you melt
it in the presence of oxygen, all you get is ash.

- and is
easier to work in that way than iron. There are cottage industries in the
Himalayas salvaging the discarded food tins and other kit dumped by rich
tourists and mountain-climbers to re-use in water-pots, cooking utensils,
roof panels, and stoves (and tourist trinkets). Extracting aluminium from
ore is horribly difficult, but once you have the raw metal you can re-cycle
it easily enough.

But only if you can achieve that inert atmosphere, which isn't trivial.

Fire removes oxygen from the air pretty effectively.

Can be arranged, I suppose.

I think it can be
done 'low tech' - the clever chaps up in the Himalayas seem to manage the
trick,

Are they working with Al, though? Tin cans are usually plated steel,
for example.

and I'm sure they don't have too many bottles of liquid nitrogen.

I wouldn't bet on anything, but you're probably right.

Stone tools - well, they'll
make you less of a target in some ways, won't they? And they're still
better than metal for some jobs - I've heard of volcanic glass blades
being used for fine surgery in recent years: better than steel.

And diamond is popular for drilling and grinding things. But the right
sort of stone is not scattered about everywhere uniformly, and spotting it
is a skill in its own right. Stone-age Europeans went to enormous trouble
to get the right sort of stone for the job - including very large mining
operations and trans-continental trade.

<grin> True enough - but it just so happens all I'd have to do is move
to Norfolk and follow the maps to the best flint in the world. Britain
is very well supplied with excellent flint.

Those parts of the country will be hotly contested once again if we really
start to need flint in quantity.

Why should they be?

Perhaps the ancient fortifications will
be re-commissioned to keep strangers out once again?

Not sure that they ever did that. Keep enemies at bay, but why worry
about strangers?

And from what I've read of the long-distance traded items, they weren't
how you got your everyday tools - it was more for the `special' stuff.
Fancy objects clearly not made for `regular use', you know?

Some of the 'regular stuff' was traded too; I've read of Norfolk flints
being found in Mediterranean and Baltic countries, for instance.

Given that it's the best in the world, that's not much of a surprise.
The stuff *here* that was imported was the fancy stuff, I should have
said.

Those
fancy foreign trophies found in Britain had to be paid for somehow.

Or something else done to acquire them. We don't know how these things
were done back then.

Fire making - ah well, now I've seen how to do the job with two
sticks, I reckon I could be relied on to get a fire going most of
the time (assuming it's not *too* wet) if I really had to. I
suppose I really ought to give it a go - the two sticks method -
sometime this summer (call me a wuss if you like, but I might as
well make it easy for myself first time around).

There are web sites about that sort of thing. Of course. I think the
pump-type fire-starters are probably the most promising 'primitive'
design,

Hardly `primitive' - that's quite advanced technology, is that.

Developed first by stone-age tribes :))

So? The stone ages lasted a very long time - and pump-type fire
starters turned up rather late on, didn't they? `Primitive' refers to
the first stuff, surely?

'Not derived from anything else'.

Hmm... But it must have been - because you have to discover the
principle of compression heating before you can apply it to make fire.

No less ancient or sophisticated than
the boomerang or bow, I suspect, for example.

Hmm - takes more to make a tube/piston arrangement than it does to make
a bow or boomerang, more by a long way.

Things made of wood tend
not to last very long in the archeological record, and if your old
fire-pump was broken or worn out why wouldn't you carve it into something
else, or use it as fuel? Add to that the fact that archeologists and
ethnologists can't recognise something for what it is until they already
know what it is (if you see what I mean) and it's easy to explain why
Europeans didn't notice 'natives' using fire-pumps until European
engineers had started to market big iron ones. 'Turned up' really means
'noticed and understood' doesn't it?

Yep.

although harder to make than two sticks.

I just like the elegant simplicity of the two stick arrangement,
although I'd like a go with one of the pumps.

Using friction to start fire is a lot of work.

Umm. I've seen it done on `one of them internet videos'. If you use a
bow, it really isn't that troublesome by the look of things. Okay, the
demonstration was done indoors in a warm dry room with still air, and
the wood was clearly dry as a bone.

A fire-pump or 'flint and
steel' is much quicker and more reliable.

Fire pump, maybe. Flint and steel? Not so sure. More convenient in
some ways, for sure - but, for example, the `spinning stick' produces
its own `ignition tinder' while you're twirling it. I suppose great the
thing about a flint and steel arrangement is that you can carry the
whole lot - ignition tinder and all - in small sealed boxes.

We call them 'pocket lighters' these days ;))

Yeah, yeah...;-)

[...]

(Old-timers who actually remember using them, say that electric
cycle lamps still haven't evolved to be as effective as the good
carbide lamps of old

Oh, they have, to the extent that they're a *LOT* more effective.
But the thing is that road vehicles are governed by legislation
that places limits on the technology so as to limit the light
output -

That's probably true for motor vehicles; pedal-cycles still struggle
to get enough light to be visible let alone to see where you're
going - there are limits to the output of a dynamo that doesn't
bring you to a standstill and you don't want to lug a big battery
around. I don't know if LED beam-throwing cycle headlights are
legal yet,

They've never not been legal.

They were when I was last actively cycling;

Hmm - well, that's not what they told me in the cycling shop down the
road, and it's a proper cycling shop run by a tiny mad old cyclist.

the two main irregularities
were the 'colour'

I was thinking of the white ones.

There were no 'white' ones circa 1990.

No, but you could get bi- or tri-colour LEDs (two or three LEDs in a
single package) that'd approximate white.

and the technical fact that an LED is not a 'steady'
light-source - it flickers, even if it is set to flicker too fast for the
human eye to notice it still flickers and that was in breach of the
regulations as they were then (circa 1990).

There's no particular reason to make an LED light flickering. And
surely if it's flickering too fast to see, it can't be said to be
flickering in the intent of the law?

If the law says 'a continuous steady light' then that's what it means;
didn't matter that the human eye was too slow to be aware of the lack of
continuity.

But one could argue that `continuous' and `steady' refer to `what a
reasonable man' would consider `continuous' and `steady' - and he'd say
if it looks continuous and steady, then it is and never mind that it's
flickering at 40kHz or whatnot.

Cyclists were successfully fined for being 'without lights'
when equipped with LEDs only.

Surely the law would have to prove that the lights were flickering in
each case?

Mind you, the idea that the flicker rate too fast to see - well, I've
noticed that car rear lights of the LED persuasion *are* driven by AC,
and I can see the flicker when I move my point of view around - you get
a strange `strobing' effect.

I think that may be to do with the prisms in the 'lenses' around the LEDs;
on your bike you probably make much greater and quicker lateral movements
relative to the vehicle in front than a car-driver could,

Nothing to do with the movement of the bike, and everything to do with
the scanning of my eyeball across the scene.

and thus move
your eye through what is effectively an array of narrow beams rather than
a solid beam such as you'd get from a single incandescent bulb.

What it is is that you scan the beam across your retina and as you do
so, the signal flickers on and off and I *REALLY* notice the effect: I
see this alarming disorienting flicker.

Doesn't matter whether I'm on my bike or on foot on in a car: it's all
to do with eyeball movement.

btw, I spotted the colour separation problem of the DLP (digital light
processing) or DMMA (digital micromirror array) `mechanical telly' at a
Texas Instruments demo some year ago pretty much the same way - I
scanned my eye across the picture and the colours (being projected
sequentially, rather than at the same time) separated out, giving a
strange rainbow-edge effect to objects on screen.

Okay, I was stress-testing the display given that it was a demo. I
tried to think of a way of doing that, and moving my eye about the
projected image seemed like a good thing to try. And bingo! Seems I'd
hit upon one of the `bothers' that they'd hoped no-one would notice.

btw, the big DLP/DMMA projector rigs they use in cinemas for that sort
of thing have one mirror array for each of the three primary colours;
you can't get colour separation due to time effects, but you can get
mis-aligned optics causing steady colour fringing if it's not set up
right.

The 'colour' aspect has
improved with 'white light' LEDs having been invented and the tuning of
output colours is getting pretty good now. There are certainly LEDs being
used in car etc rear lamps and indicators now so presumably the 'flicker'
has been accepted in the current regulations

Yeah, but I'm not happy with the car gear. I've never noticed `flicker'
from bike lights set to `steady'.

Pedal-cycle LED lights so far are mostly pretty basic; also fewer actual
LEDs than in car indicators.

Erm - and?

[snip]

Costly temperamental dynamo systems and clunky ugly
battery lamps with significant running costs were never going to appeal to
those concerned about appearance or speed or expense above all else.

I've got dynamo lights /and/ LED lights. And lots and lots of
reflectors all over the place. And fluorescein (my spelling checker
tells me that's right, but I'm not convinced) bicycle clips from my
trousers.

I think your spelling checker is thinking of a substance rather than an
effect.

The substance is what I was looking for. Fluoresence is easy to spell.

I too had both dynamo and battery lamps on my commuting pedal cycle - and
LED rear lamps when they became available, in place of incendescents
(there were conversion gadgets for existing battery rear lamps; not
strictly legal at the time but good enough to fool the plod if the lamp
looked like the legal sort -and they paid for themselves in batteries not
used, very quickly). If I was expecting to ride 'off road' (eg
along a tow-path or across the marshes) after dark, I'd take a head lamp
too - the sort you strap to your head. And I always had a blinking red
LED thingy attached to the back of my fluorescent 'sam brown' or 'courier
bag' so that if I did have to dismount (or fell off) I wouldn't suddenly
become invisible. Very reassuring when fixing a puncture.

Oh, please stop it blinking! That's not at all helpful, it really isn't
- makes you harder to spot, I promise.

although they're certainly in use, but they're still in the pocket
torch class for lighting your way - ie barely enough.

Depends how they're made, really. If you do the job properly, you'll
get more light and a better spread of light with LEDs than incandescents
- and you'll need less power.

There's some way to go yet, in practice. When 'white' LED designs are
pretty uniform and the cost is low enough, I expect makers will put more
effort into making the reflectors and lenses in the lamps more effective.
Current designs seem to depend mostly on the optical characteristics of
the LED capsule itself, which is rather variable.

True, but there's no reason why that shouldn't receive proper attention.

I'm sure it will. Expensive hand lamps are leading the way.

Mmm - if the devices exist, they can stick 'em in anything.


[snip]

We did use billy-cans instead of saucepans sometimes, although that
was a bit flash (ie you had special stuff just for hiking; posh).

<grin> Righto. And tell me, did you have proper sleeping bags, or was
it the old `two blankets sewn together'?

Pinned together, using 'blanket pins' - giant heavy-duty safety-pins.

Ah!

People were starting to get 'real' sleeping-bags, but they were heavy and
expensive

My father had an old fashioned sleeping bag filled with goose down,
purchased in the 1950s, IIRC. I slept in it one particular night which
was the only night I've ever got wet under canvas. I woke up very soggy
- but warm.

`Totally brilliant', was my judgement.

- and not a lot better than a good blanket and a bit of tarp (or
a good solid canvas tent and fly-*** and oil-skin ground ***). The
things made with silk and eider-down were far too expensive,

Cotton and goose down works pretty well.

and kapok is
ghastly when it gets wet.

Oh god yes.

Nylon dries quickly, but it isn't terribly
'warm' and the static can be alarming.

Yep.

Rowland.

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