Leonardo Notebooks (Again),impressive Entrance Anyone?

[Khandro]

Having moved on from 'The Nature of Water' I find in 'Experiments' the following, would anyone care to try;
'If you wish to make a fire which shall set a large room ablaze without doing any harm you will proceed thus: first perfume the air with dense smoke of incense or any other strong smelling thing, then blow or cause to boil and reduce to steam ten pounds of brandy.
But see that the room is closed altogether, and throw powder of varnish among the fumes and this powder will be found floating upon the fumes; then seize a torch and enter suddenly into the room and everything will become a sheet of flame.'

[Baldric]

Please do not try this at home!

[Mamyalynne]

Don't fancy trying it but it certainly conjures up an image worthy of any fantasy film.

[ChuckFickens]

Sounds like a waste of ten pounds of brandy to me.

[jake-the-peg]

Not *that* impressive in the context of Greek fire being used hudreds of years earlier.

http://en.wikipedia.org/wiki/Greek_fire

If you want something impressive in early science I've yet to see anything that even comes close to this.

http://en.wikipedia.org/wiki/Antikythera_mechanism

For those who've not come across it it's a multi-gear wheeled calculatr that works out the movements of the heavens.

It has 30 gears all working together and was made over 100 BC quite possibly by Archemedes

By comparison Leonardos geared mechanisms look hopelessly crude

It's not unreasonabl

http://www.youtube.com/watch?v=L1CuR29OajI

[Khandro]

jake; Yes the antikythera mechanism is amazing, I saw a tv prog. devoted to it not long ago. It isn't fair though to say Leonardo's geared mechanisms look hopelessly crude by comparison.
Leonardo didn't actually make machines really, he mostly made simple, very small sketches of them (the notebooks are tiny), sort of 'back of a fag packet' drawings; I'm sure whoever was responsible for the mechanism made lots of similar sketches in the first instance, before handing over the construction to a team of skilled metalworkers.

[aelmpvw]

don't get much brandy for a tenner these days ...

[jake-the-peg]

Well - I don't know - there were some pretty skilled metalworkers in the renaissance but we didn't see anything this good 'till the eighteenth century - some might even claim until people like John Harrison and Breguet.

I think that's the difference - Leonardo seemed interested on a theoretical level I suspect he lacked the patience to really work with someone and get something to work - his designs always seem as you say 'fag packet'

That's not to denegrate him - he was still streets ahead of his contemporaries but I think we're very privileged, I think in the in the antikythera mechanism we are looking at the handiwork of one of the greatest minds that has ever lived.

I mean Hero of Alexandria had some great designs with early steam curiosities and I think you could compare his designs with Leonardo's

But this is an order of magnitude above - It's like finding an internal combustion engine inside the pyramids!

[Khandro]

jake; //It's like finding an internal combustion engine inside the pyramids!//
That's true looked at from our perspective, because it appears to us to be in isolation, but it must be part of something larger. It appears unique because it is unique to us, the people responsible for making the machine didn't presumably begin and end there. So much has been destroyed both accidentally and wilfully, and was probably recorded and lost in the fire of the library of Alexandria.

[heathfield]

I've seen some of Leonardo's original drawings at first hand, and many are tiny What puzzles me is how he managed to draw such fine lines if he only had the use of a quill pen. Some of the miniature images look as if they've been drawn using a Rőtring 0.1mm nib!

[Khandro]

heathfield; Yes they are amazing. I think the answer is that as Signorelli visited Dürer who amazed (and still does) the world by his fine lines describing hair etc, asked him how he did it, and he wrote how Dürer picked up a rather ordinary small brush of the time, charged it with thin paint and drew an extraordinary fine line. It is a matter of having the skill to just touch the surface with the very tip of the brush in the lightest of manner. Leonardo had the same skill with a pen.

[askyourgran]

Leonardo was a genius, although setting fire to 10 pounds of brandy is a hell of a waste.....ttfn would be thuddding all over the place, I reckon it's half a bottle easy. I wonder how he managed to test this experiment 'entering into a room suddenly and everything becoming a sheet of flame'. Minus his eyebrows...

[heathfield]

Come to think of it, artists brushes comprising a single hair are not all that uncommon. Maybe he used one of those to do his drawings. The only problem then would be mastering the flexibility of the tip. I wonder what his neighbours would think about his brandy vapour experiment after it had reduced the building to rubble? ;-)

[Khandro]

The brushes you refer to as 1 hair or 'a fleas eyebrow', are not much use for making anything like a long line because they are unable to hold paint. What is needed is a brush with sufficient hairs to hold the paint and coming to a single hair pointed tip.
Another type is called a 'Rigger' which is long and thin, and so called because it was produced for painting the long fine lines of masted-ships rigging.

[Teddio]

Is Leonardo describing a dust explosion here (powder of varnish)? Most coal mine explosions are caused by the ignition of a pocket of methane gas whose shock wave lifts up a cloud of coal dust, which subsequently explodes.
Custard powder works equally well !