Anatomy Atlas Part 22 – Eye

For humans the eyes are probably one of the most important senses. They are definitively for me, so two years ago when a willow twig slashed me across one eye the pain was a mere secondary concern to the fear that an infection might cost me the whole eye. I did not hesitate and immediately sought medical help, got antibiotics and atropine and the eye healed in just a few weeks. Ever since then I am wearing eye protection when pruning willows, in addition to all the other jobs I am used to do so.

Description of an unpleasant  and cringe-worthy incident follows.

©Charly, all rights reserved. Click for full size.

Incidentally just a few days ago I had a short conversation with the cleaning lady at our lab about this. I have made some mess that I did not manage to clean up before she arrived to mop the floors and I was apologizing to her for this. Her response was that it is her job to clean the floors and mine was that I know but that is no reason for me to do her job unnecessarily harder by not sweeping the aluminum shavings after I am done. After which she remarked in a passing that her former boyfriend was drilling aluminium when doing some renovations, he was too macho to wear an eye protection and got an aluminium shaving in one eye. And after that he was too macho to go to the doctor immediately, saying “it will rot away”.  And it did. With the whole eyeball. She finished “now he has one glass eye, and I have found myself a better man.”.

An example of how toxic masculinity is harmful, if I ever saw one.

Most people know at least something about the eye anatomy I guess, but I would bet most people do not know about the muscles musculus obliquus bulbi superior and musculus obliquus bulbi inferior.

These muscles can rotate the eyeball slightly around the front-back axis. Why is this? you might ask.

Generally the muscles around the eye, when you are looking at something, try to keep the picture you see static and at the center of focus, even when you move. So when you look at your monitor right now and tilt your head to left and back, your eye bulbs will rotate in the sockets in such a way as to keep the light falling on the same parts of retina throughout. That is also one of the reasons why human eyes cannot “pan” like a camera, but always skip from point to point.

It was explained to us that the purpose of this is to save the brain from getting overloaded with constantly changing stimuli. When the eye is fixed, it delivers constant signal to the brain from most of the retina, and the brain then can concentrate only on that which is really important – i.e. that which changes on its own.

I do not have the knowledge to challenge this notion, but I must say that the brain-software that keeps the eye focused and immobile relatively to the thing we are looking at must be pretty impressive too, with all those feedback loops reacting so quickly as they do.

Making a Rondel Dagger – Interlude 3 – Dubbin

With the work done, I have to protect both the leather covering of the scabbard and the iron fittings against the elements and medieval appropriate medium for that is so-called dubbin or leather food. Google does yield some recipes, but I did not bother searching for or following an exact recipe much – once I have known the rough composition, I plunged right into it as is my wont.

Ingredients in the mug.

So I took a stainless steel mug, put in it a piece of lard, about the same amount of unrefined beeswax (twenty years old, btw.) and I poured an “adequate” amount of olive oil on top of it. Then I lit the fire and stirred until it all melted together. It was quite interesting to watch – the pig fat dissolved of course first and the big beeswax piece last, but it did not take too long. In fact, it was over in mere minutes. I have measured the temperature and when it all was blended together the liquid had about 80°C. High enough to be dangerous, but not so high as to melt plastic or hiss in contact with water. It remained liquid long enough to touch with bare hand.

Finished dubbin in a plastic container.

Even so when pouring it into a plastic container for keeping, I have put said container in an even bigger one and poured cold water around it just to be sure. As you can see, the liquid has had a honey-like colour that I have found rather pleasing to the eye. It does not smell too bad either and when the product cooled enough to be touched by bare hands, I have simply dipped my fingers in it and applied it to the scabbard in no small amount. In fact I sloshed liberally all over it, making an uneven layer that was in parts over 1 mm thick.

Dubbin applied to the scabbard.

That of course does not look very pretty, so I took a heat gun and melted it all until it sunk into the surface. I was careful however to not heat it too much – just about to melt it and no more. Leather does not respond too well to heat and I did not want to damage it.

When that was done I rubbed the scabbard first with a paper towel which took off some of the excess dubbin, then simply by hand. The dubbin is actually relatively pleasant to touch – not unlike a hand lotion in fact, although it is more solid.

The leather strap tied around the scabbard unfortunately did not survive this – it was made from recycled leather of poor quality and tore off. I have cut a new one and this time I plied it with dubbin before tying it around – and that seemed to have worked rather well. The dubbin made the old leather soft and pliable and also sleek, so it was much easier to pull it through the holes and tie the knots than in my previous attempts.

I intend to buy a soft bristle brush at nearest opportunity that will be used for this substance exclusively. It has hardened into a yellow mass that looks like refined beeswax but is much softer to the touch – but not creamy as a hand lotion. I have labeled the lid of the plastic box and I have stored it in my workshop for future use. I think I got carried away a little here and made possibly a life’s worth supply.

If it goes rancid I will let you know. I hope not. And next time you see the “Rondel Dagger” title, there will be pictures, I promise.

Dubbin.

Behind the Iron Curtain part 16 – Languages

These are my recollections of a life behind the iron curtain. I do not aim to give perfect and objective evaluation of anything, but to share my personal experiences and memories. It will explain why I just cannot get misty eyed over some ideas on the political left and why I loathe many ideas on the right.

In Czech we have a saying – how many languages you know is how many times you are a human. As a grown man I do appreciate the wisdom of this saying, since language barriers are difficult to breach and in combination with other things they do lead to a lot of nasty stuff. It is for example very easy to other people whose language you do not understand and with whom you therefore cannot effectively communicate. Even with all other barriers removed, language barrier in itself can be insurmountable obstacle. And when you can and do speak with people, all other differences tend to fade away.

As a child, I did not appreciate the saying at all. My parents were trying to get me to learn German from early age, but since they are not the pushy type and I was not too receptive, it did not work out. Later at school from age 10 Russian language was compulsory. But there we hit the snag of not only another language, but another alphabet as well – for me it was difficult enough to learn writing in one alphabet and sure enough, another one was difficult even more and soon I started to write fluently but illegibly in Azbuka as well.

I do not remember whether the explanation as to why we must learn Russian was given to us as a matter of course or whether someone asked, but it was given to us nevertheless. It was argued that it is useful to know at least one widely distributed language so one can communicate with more people. And that most widely distributed languages are English, Spanish and Russian, because USSR covers one eight of inhabitable land and Russian is spoken in all other countries of the Warsaw Pact, covering most of Europe and Asia, therefore Russian is the most useful language for us of them all. Q.E.D.

You probably have spotted already the flaw in that argument, as did I – the area of inhabited land is not as important as the amount of actual people with whom you can speak using given language. But lacking further data, I have not questioned the wisdom of this and I thought that it is a valid argument at the time. So I plodded on with difficulties trying to learn Russian, torturing my teacher in turn as much as she tortured me.

However it did not take long to learn how untrue this argument is in real life. It started when I saw how difficult it was for children to get help with homework in Russian language. Nobody could read it and nobody understood it much, despite the fact that they all learned it in school. That way I learned that actual use of Russian among ordinary people was so minimal that most of them forgot most of it as soon as they left the school. Second observation was when I was at a summer camp in German Democratic Republic. We were allowed to have some pocket-money and to do some shopping. Hooray! We are in a foreign country, but people here learned Russian in school, therefore we will be able to communicate with them! And to this day I remember the totally blank expression of a quite young shopkeeper when I told her that I would like to buy that aeroplane model of – (I forgot the exact type) and I had to resort to pointing and grunting instead. Huh, so much for that argument then.

By the time my elementary school education was nearing its end, I was convinced of two things – first was that I am hopeless at learning other languages and I hate it. Second was that learning foreign languages is nearly useless.

For the second conviction I actually had some solid data at the time – the Iron Curtain was an effective barrier going anywhere west of my home, making any need to understand people living there moot. And from experience I knew that even if I manage to get to some of the other eastern countries, Russian will be of nearly zero use.

To this day my generation and those older are still the least language-savvy generations in our country. And the country as a whole has therefore still abysmal proficiency in other languages, as well as in many other former east bloc countries. The Iron Curtain persists in this form, still fostering xenophobia and bigotry. A reminder that a regime change is not enough.

Last Sunflower Resident

The sunflower is now slowly drying, all the heads full of seeds. But when it was still in bloom, I encountered on it this beetle, one that I have never seen before. I have recognized that it is a member of the family Cetoniidae (flower chafers) but that was it.

I think that it is mediterranean spotted chafer Oxythyrea funesta, which was preliminarily confirmed to me by an actual active biologist. In that case, it is a rare sight because the beetle is rare in Czech Republic and is protected by law.

©Charly, all rights reserved. Click for full size.

Youtube Video: Nurgle Plague Sword Build

Michael Cthulu is not a smith, he is a welder. And he does not make historically accurate replicas, he makes ridiculous, humongous swords from computer games that have no chance whatsoever to being actually functional in the real world.

But he is entertaining to watch and he has shown some tricks in his videos that are valuable to me in my workshop – like his unique working goggles with replaceable glasses.

He also seems to be a genuinely nice person, at least judging by the ammount of his products he auctions for charity ever since he makes enough money for comfortable living.

Mild content warning – the video takes almost an hour and contains half-naked and very hairy dude in his fifties doing dangerous things with fire, electricity and fast spinning machinery.

Itsy Bitsy, Lean and Mean

This is the last in this Itsy Bitsy Spider week, that has gone on for almost two weeks. That does not mean however that spider contributions are not welcome anymore. Should you come across some pretty specimen, definitively take a picture to share.

Today’s picture is from rq: Just a lean, mean, bug-eating machine hanging out.

Picture is bellow the fold.

[Read more…]

Pollination Party – Ants and Flies

I truly am envious of Nightjar’s flowerbed.

Nightjar notes: Ants are not very good pollinators, but they definitely show up for the nectar buffet, as do flies. One curiosity I was told about the Stomorhina lunata is that the larvae feed on, very specifically, locust eggs!

©Nightjar, all rights reserved. Click for full size.

Acanthiophilus helianthi and an ant.

An ant. On a flower. In a picture.

Eristalis tenax a bee mimicking hover fly.

Stomorhina lunata

 

Anatomy Atlas Part 21 – Heart

Heart. An organ whose importance was known throughout the history, but whose real function was not.

©Charly, all rights reserved. Click for full size.

The one interesting fact about heart that springs to my mind is that one of the most important discoveries into how it actualy functions was done by a Czech anatomist Jan Evangelista Purkyně who discovered the specialized impluse-conveying neurons in 1837 (but I had to look that date up, since I have terrible memory for numbers). They bear his name “Purkynje fibers”.

I wonder whether kids in other nations around the world get to hear his name when learning about heart.

Making a Rondel Dagger – Part 16 – Chape

I had a very busy Sunday. My vacation is nearing its end and I have been hell-bent on finishing this project already, but things got in the way all the time.

The biggest problem with the chape was that I could not find any information about how to do it properly. There are some pictures of finished products  and some info about casting them from bronze, silver etc. but not about how to form one out of steel. So I had to start from scratch.

My first two attempts were completely unsuccessful. I do not even have anything to show you  – you are free to imagine some vaguely rectangular and bent piece of metal. What I am going to show you is my third – and final – attempt. I do not call it a success either, but it is at least big enough part of a success to yield a usable product. But I am not satisfied with it and I had to repress the urge to hurl it out of the window with great force.

In retrospect I think my biggest mistake overall was using too thick steel. The shovel that I was recycling was ca 1,5 mm thick and for this purpose probably half that thickness would be appropriate. Unfortunately I did not find any suitable piece of steel in my scrap pile.

Should anyone wish to avoid some of the mistakes I have made, here is the most important thing I learned: do not try to do it without dies and templates. It is a complete waste of time. Chape is a very complex piece of metal, bent and formed in multiple directions at once.

I wanted only the front face to be pretty, but even that has proved to be beyond being doable without a template, definitively without  a skill that I lack. And since I  also lack screw press, I had to do with my vice. So I have built a set of jaws – one formed approximately as the tip of the scabbard, and one with a matching hole about 2 mm bigger on all sides. After this I have heated a piece of steel, put it between the jaws and pressed it as quick as possible. After a few repeating and some repairs/adjustment of the jaws I have finally got a  shape that at leat partly fitted the tip of the scabbard. I might be on the right track here.

However, after a few presses the metal had nowhere to move – so I have cut it into stripes that I have intended to bend around the scabbard. I have again made the mistake of trying it first without a template. Again, complete waste of time.  I have only managed to bend them so they point straight to the back of the chape. I could not achieve the second bend to close the flaps around the backside.

So I had to fish around in my scrap pile some more. Two cuts that were left over from making the jaws have proved to be useful here – when put back to back, they were the same thickness as the wooden scabbard, therefore I reasoned I could make a template out of them.

So I took an angle grinder to them and made two nearly identical halves that mimicked the wooden scabbard. A few touches with a file were also needed in order to round the edges etc. I am not going to toss these, I am going to keep them as well as the jaws in case I need to do similarly shaped chape again.

I have deliberately made this template so most hammer blows will be perpendicular to the vice jaws. No matter how strongly you close the vice jaws on anything, hammering or filing/sawing it will eventually loosen it or break it. That is actually a reason why specially formed jaws with a groove have to be used for holding round stock.

With this I was finally able to bend and hammer the steel flaps all around so the fit more or less snugly around the tip of the scabbard. I did not want to close it all the way around and I intended to leave the stitching visible, because it was more or less clear that I will have to hammer and ever so slightly bend the finished chape onto the tip so it holds and does not fall of. However, I wanted to at least braze the gaps on the sides. I failed to do that, because I run out of silver solder and I will be damned if I spend another 10 € on this. At this point, I was starting to hate the thing. So I brazed as much as I could and sod the rest. Here you can see it all black, covered in solder and slag and scale. I have again carefully ground the excess solder with fine file and collected the silver dust, but I still did not feel like experimenting with making solder out of that dust.

This is when It I have got the only idea during this whole process that I consider valuable – I have found out that old, nearly worn angle grinder wheels are excellent for scraping of the scale and the slag – both of those are harder than files and they tend to smear abrasive papers. So a bit of water now and then to wash of the dust and a bit of scrubbing with an old wheel and I could proceed to polishing without covering my belts with grime. Polishing I have performed the same way I did with the throat. During this I have found out that the chape is much more asymmetrical than I was hoping for and that there are two poorly brazed spots on the sides. leaving unseemly spots, but as I said, sod it, I am not going to do this thing again.

When the chape was finished, I have put it and the throat on the scabbard and gave both parts a few wallops with a wooden mallet on a wooden board so they hold in place (for the throat I had to put a piece of leather on one side between the backside of the scabbard and the throat for better fit). And then I walloped it all some more so it holds.

So now the project is almost finished. All that is left to do is to sharpen and sign the blade, tie a leather strap around the scabbard and treat it with dubbin and make pictures. Neither of those things should pose any big problems and except the signing they cannot destroy anything. I hope.

Despite being a non-believer, I do understand the desire to be able to pray – a desire to have some control.