“Comrades cadets, in wartime the value of cosine can reach 2, and in exceptional cases, when the situation on the fronts demands it, even 3!”

“Comrades cadets, in wartime the value of cosine can reach 2, and in exceptional cases, when the situation on the fronts demands it, even 3!”

Today a big interesting historical post.
Where I was: Historical Museum of Military (Civil War) Medicine in Frederick, MD. Entry is $9, $15 with a guide. For an hour and a half, we got a very smart guy who gave an interesting lecture, making the provincial museum really very interesting. We even tipped the guy afterward.
A few interesting facts that I didn’t know before. During the Civil War in the USA (1861-1865), there was a monstrous scale of losses – over 600,000 people. One in every ten was mobilized for the war. That is, excluding women, children, and the disabled – yes, someone from almost every family fought.
Apparently, Americans were not very experienced in wars back then, and organizing large groups of people was based on the “fend for yourself” principle. From gastrointestinal diseases alone, nearly four times more people died than from wounds. Soldiers cooked everything themselves – there was no cook or porridge for the platoon. They split into micro-groups of a few people, pooled whatever they had, and fried it on a fire. For some reason they mainly fried, not boiled (which also contributed to diseases). Their main rations were salt pork and hard-tack β crackers as hard as a stone. Fried hard-tacks were called Skillygalee.
Remember, it was not like that in European wars. And all because there were many of them, and they quickly figured out how to make them more effective. Plus, there was also a civil war, poorly organized and spontaneous.
Initially, soldiers were handed money in the field and they sent it to their families as best they could (not all reached its destination). For Southerners, money devalued faster than they could carry it to the tent. Back then, each state issued its own money. They write about 8000 different banknotes at that time. I didn’t quite believe it, started researching, and it turned out that this is still a very conservative estimate. Yes, anyone (state, city, private bank, railway, factory, and even a pharmacy) could print their own paper money. Each bank issued banknotes of its own design for different denominations ($1, $2, $3, $5, etc.). In 1860, there were about 1600 private banks in the USA, and almost each issued its own range of notes. But in the end, greenbacks – federal money prevailed.
They also told us about Dorothea Dix, the head of army nurses for the Union. She introduced an interesting age standard for the nurses. No “young and beautiful.” Only women over 30 years of age, “plain-looking,” no jewelry, fashionable dresses, or crinolines – only strict brown or black dresses. At that time, the appearance of a woman in a male military camp was considered almost indecent. Dorothea wanted the soldiers to see in the nurses strict mothers or aunts, not objects of flirtation.
To join the army, a volunteer was required to have at least two teeth opposing each other. Why? A soldier needed to quickly bite off the tip of a paper cartridge to pour the powder into the barrel. No teeth β you’re useless in battle.
Back then, they shot with MiniΓ© balls – made of soft lead. It was huge caliber (thumb-sized) and when it hit the body, it didn’t just pass through, it “burst” and literally turned bone into fine crumble. Repairing such a bone was impossible, so amputation became the only way to save a person from gangrene. At least there was some form of anesthesia (chloroform/ether).
Before the Civil War in the USA, people were buried where they died. But the war generated a demand: affluent Northern families wanted to bring their sons’ bodies home. That’s when embalming flourished. Right behind the front line were tents of “embalming surgeons” who for a decent sum (about $50β$100 for an officer) extracted blood and injected chemicals (arsenic and zinc) into the body. Actually, the museum building included such a place. Lincoln’s body after his assassination was transported across the entire country on a train, and it looked “alive” thanks to this new technology, which became the best advertisement for the new industry.
Overall, Frederick is a very nice city, full of art and nonconformists π Like our Leesburg, but 20 times bigger.
P.S. It was interesting to study what drove people to go die. Of course, our guide said “patriotism”.
But if you google, it turns out not quite so. Of course, in 1861 no one knew that the war would last 4 years and take 600,000 lives.
Reason #1 – boredom. Life on a farm in the mid-19th century was incredibly monotonous. War seemed like the greatest adventure in life. Guys thought: “I’ll go, see the world, shoot, become a hero, and then return to harvest.”
Reason #2 – naivety. The first volunteers went to the front as if on a picnic. In the first major battle (Bull Run), civilians from Washington even came with picnic baskets to watch the “spectacle,” until they were swept away by the retreating crowd of bloodied soldiers.
Reason #3 – “honor.” In the 19th century, “honor” was not an empty word. If you were a healthy guy and didn’t go to the army, you became an outcast in your own town. It’s written that girls often refused to go out with those who didn’t wear a uniform.
Reason #4 – “regimental solidarity.” As I already said, regiments were formed from neighbors. Not going to war meant betraying your friends, brothers, and father. Shame before neighbors was stronger than the fear of death.
What did they fight for?
Here the goals of the North and South radically differed:
For the North, the main idea was “Integrity of the Union.” For them, the USA was a great experiment in democracy that could not be allowed to fail. The slogan “Save the Union” was more powerful than “Free the Slaves.” At first, not everyone was ready to die for abolition of slavery.
For the South (Confederacy), the main motivation was “Defending their homes.” Most Southern soldiers did not own slaves (slavery was too expensive a luxury for ordinary farmers). But they were convinced that the “Yankee northerners” were coming to seize their land, burn their homes, and impose their rules. They saw themselves as heirs of Washington, fighting against “tyrant” Lincoln.
Reason #5 – bounties
When initial enthusiasm faded (by 1863), pure calculation played its part. States and the federal government started paying huge “enlistment bounties.” A sum of $500β$1000 was equivalent to a few years’ earnings for a laborer. For a poor immigrant (Irish or German) just off the boat in New York, it was a chance to provide for a family or buy a farm after the war.
In 1862-63, both sides introduced the draft, as volunteers were running out. This exposed social injustice.
In the North, you could officially avoid the army by paying $300 (huge money for a poor man, but manageable for the middle class) or find a “substitute” (a person who would fight in your place for money).
In the South, there was the “Twenty Negro Law.” Owning 20 or more slaves exempted you from service, as you were “needed in the rear for production control.”
This caused fierce resentment among ordinary soldiers. The famous “Draft Riots” in New York (1863) were sparked precisely by this sense of injustice.
So there you have it π


Semikhatov’s movie about gravity turned out to be really cool. Of course, it’s quite popular, but understandably so – they didn’t want to scare off the audience. Itβs very cool and professionally made.
I have Semikhatov’s book on my shelf (“Everything That Moves”). It’s also popular, but itβs a bit more serious in its presentation, at times with formulas and loaded with illustrations. Later, my opinion of him slightly soured due to his specific way of conducting podcasts, constantly interrupting guests and answering his own questions in a way that outshines the guest demonstratively. But in the movie, he looks absolutely great. I recommend it.
The link is in the first comment.

Reading Nabokov, there “…with the dash of the Danube in his veins…”. Turns out, Danube is ΠΡΠ½Π°ΠΉ. But that’s okay, trivial stuff, the interesting thing is something else. That Don, Danube, Dniester, Dnieper, Donets, Dvina, and Disna essentially mean more or less the same thing – river. Apparently, the ancient people were not always rich in imagination when it came to toponymy. If you live by the water, you simply call it “River”. Over time, others came, heard this word, took it as a proper name, and altered it slightly to fit their accent. This way “River” (Danu) transformed into a dozen different names across the map of Europe.
The river Volga essentially is also just “river”. Okay, slightly different, “Volga” comes from the Proto-Slavic *VΓ²lga, which literally means “moisture” or “water”.
Also, it turned out that the Sahara desert is named so because Sahara (Ψ§ΩΨ΅ΨΨ±Ψ§Ψ‘) is desert. And the Gobi desert is called Gobi because Gobi in Mongolian is desert.
While googling, I stumbled upon another fun thing. There’s a place in England, Torpenhow Hill. The name is composed of four different linguistic layers: Tor β in Old English “hill”, Pen β in Cumbric “hill”, How β in Old Norse “hill”, Hill β in modern English “hill”. Result: “Hill-hill-hill-hill”. Likely, each new people arriving in this area didn’t understand that Tor, Pen, and How were already names for the hill, and added their variant of the word “hill”.
Update: figured it out, looks like the lock needs 6v + 6v for different purposes. Maybe the power part and electronics.
Anyone who knows electronics, help me understand. Red wires are connected to contacts that respond to the tester. A total of 8 batteries. I can’t see a classic snake configuration here. Can’t understand why the lower right ones are responding. I want to connect an external adapter


Today I read that the Third World countries were initially countries not part of NATO (First World) or the socialist bloc (Second World), that is, countries such as Sweden, Switzerland, Finland, Ireland, and Austria. Some still use the term “developing countries,” where it is customary to include low-income countries, but, darn it, a developing country is actually a good definition. The one that has developed and stopped developing – that’s a signal. Incidentally, Qatar, which has the highest GDP per capita in the world, is formally considered developing.

About the English language. When Yuki sees another dog, he adorably places his chin on the ground and presses his paws to his face, but I have to tell him every time not to approach because once he lets them get closer, he suddenly starts growling and instigating a fight. And what verb would you choose for that?
Well, from school I knew that roar meant growl. And I even told everyone “roar” for the first week until I googled it and realized that in roar, it’s tigers, lions, and motorcycles, but for dogs, it’s growl or even snarl (with teeth showing).
Or take the phrase “cook food.” To cook comes to mind, but actually, to cook implies thermal processing (fire, stove). If you’re “cooking” a salad, tea, or a sandwich, a native speaker would say make. Saying “I’m cooking salad” is like you decided to boil it.
Or suppose you decided to watch a movie. In English, the choice of verb depends on where you are and how large the screen is. When you go to the cinema, you use the verb see. “Let’s go see the new Dune movie at the cinema.” If you say “I watched a movie at the cinema,” they’ll understand, but it sounds a bit technical, as if you were sitting there closely studying the screen like a security guard monitoring it.
But. When you turn on your television, laptop, or projector in your living room, watch comes into play. The verb watch implies extended attention to something on a smaller (relative to theater) screen. By the way, if the screen is off, you look at it (as an item). Once you turn it on and a picture appears, you start to watch it.
Generally, for an advanced level, it makes sense to attach each concept to a scale, to remember the words in shades of intensity. For example,
Cry -> Weep -> Sob.
Annoyed -> Irritated -> Angry -> Furious -> Livid.
Smile -> Chuckle -> Laugh -> Giggle -> Guffaw
Spitting -> Drizzling -> Raining -> Pouring
and so on.
And then further distinguish them by paired opposites, like the smile-cry from the example above.
It’s very easy to remember when put together.
But it’s necessary to try to apply them, otherwise it’s no good. Some words may be bookish, and here it’s important in what context it is said. If you told a friend in a pub: “I cannot comprehend this beer” – it would sound as if you’re writing a dissertation on that beer
It turns out that ΟΒ² β g is not some mystical coincidence. When the first scientists contemplated the definition of the meter, there was one elegant proposal: to make the meter equal to the length of a pendulum that takes exactly one second to swing from one side to the other.
For a mathematical pendulum, the period of oscillation is calculated by the formula: T = 2Ο β(L / g). If we take the length L = 1 meter and set the full period T = 2 seconds (so that it takes exactly one second for each half swing), the equation implies: g = ΟΒ² (m/sΒ²).
The definition of the meter was later changed: it was tied to one ten-millionth of the distance from the equator to the North Pole along the meridian passing through Paris. However, this geodetic definition was inspired by the earlier idea with the pendulum. Notably, both approaches match up with an accuracy of 1%. Essentially, since the old “pendulum” definition was the main candidate for a long time, values were adjusted so that the new meter was convenient and close to the measurements customary at that time.
It is also interesting that the number of seconds in a year roughly corresponds to the number of pi * 10^7. Earth’s orbital speed is about v = 30 km/s. The distance from the Sun to Earth is approximately r = 150,000,000 km. Thus, over a year, Earth travels a path of about d = 2 * Ο * r. Then, the orbital period equals T = d/v = Ο * 2 * r/v = Ο * 10β· seconds.
I’ve further developed a new tool for myself for working with information and organizing it. The main idea is a web-based notebook for research, studying subjects, working on them, integrated with AI and PDF support.
The main problem with typical PDF readers and notes is that the context is lost as soon as you switch to a new tab. In my tool, each text fragment or PDF becomes a node in a “live” hypertext tree, which I can access from multiple computers at any time.
Work process:
– Contextual AI. I can ask the AI to clarify complex passages right within the document. The explanation stays right where the question was asked. Moreover, it is a separate document, linked to the specific spot in the source. When clicked, you see both the original and the explanation on the screen at the same time.
– Panels instead of windows. If the explanation itself requires clarification, a new panel opens to the right. This allows for an endless chain of queries, never losing the place in the original text. That is, you see several panels at once, and unnecessary ones can be closed.
– PDF support. I can upload a PDF, select an area on the page (e.g., a complex diagram or a list of authors), and the LLM instantly extracts data, supplements, or explains them. The explanation is attached to the spot where it was requested, just like with non-PDFs.
– Nested annotations. My comments are not just static text. They can contain their own PDFs, links, and further sub-tasks for AI, maintaining a depth of nesting that reflects how we actually think.
This is not just a file storage system, but an “engine” for building knowledge.
The tool suits me personally very well, but perhaps it only solves my specific tasks. What do you think, would something like this be useful to others? Would it be useful to you? Should I develop the project into a fully-fledged product and give it to other users for testing?
I formulated for myself how I manage to get a lot done (actually, I don’t). It’s not a fact that it will work for others. But still, here are the points:
1. Do what you like. You need to do what your heart is in at the moment. If you force yourself, efficiency drops tenfold.
2. Sports anger as a catalyst. You need to treat failure not as a tragedy, but as a personal insult from the task. Anger is the quickest way to enter a state of hyper-focus, turning “didn’t work out” into “oh really, now watch me”.
3. Seamless switching. As soon as energy in one task has waned or the task is done β leap to the next funnel that beckons right now. It might not always be work-related. For instance, I might play the piano, draw, program, write a book, or do work.
4. Completing. Take a chunk that you can chew and bring it to a plus-minus norm. Don’t drop it midway, while there’s still momentum. Finish and refine – that’s a task for the next “high”.
5. If you can’t break through a wall β don’t smash your head against it. Mark the point of stopping, say “I’ll remember you” and retreat to return with a different tool or a different mood. The main thing is to keep this “open gestalt” in active memory and not tuck it away for too long.
6. An external promise is sacred. If you promised a deadline by Monday, personal comfort (like sleep on Saturday) is sacrificed. This pain teaches you to filter promises in the future. Your word must have physical weight.
7. The plus one principle. Always do a bit more than expected of you. How much more is a question of context, resources, desire, but the delta should be tangible.
8. The principle of useful output. Any product of activity should be in a form that can be delivered. The English word for this is ‘deliverable’. Simply getting to grips with something is not a product. But understanding it and documenting it in Confluence is a product. A letter, an article, code – anything.
9. “You gotta, Fedya, you gotta.” Perform mandatory ceremonies and necessary bureaucracy as an inevitable evil that simply has to be done anyway. Need to pass some stupid training every six months? Allocate an hour for it and suffer through.
10. Have the best tools for the task. If you don’t have them, strive to possess them and learn to use them.
Three more principles, which seem unteachable but are very helpful:
0. Don’t get irritated and don’t irritate others.
1. The ability to instantly separate the important from the junk, and the urgent from the hustle. This is an intuition that only develops with years “in the field”. And total curiosity – the ability to find excitement in any topic. This applies to everything – including who to talk to and when to go to the store.
2. If you’re bored β it means you just haven’t dug deep enough. Interest is a matter of immersion scale and having the right people, books, YouTube videos, etc. Eventually, there simply are no topics that seem boring.
3. Lifetime learning principle. Any project is a legal excuse to become smarter at someone else’s expense. Look for what ignites you in routine and what you’ve long wanted to learn. See a task that would be more elegantly solved with a script in Haskell, a language you’ve never seen before? Then today, we are learning Haskell. True, enthusiasm should not bury the deadline. You need to deliver results, even if the experiment completely fails. Promise foundation first, then decorate with the new skill.
These principles have a downside. For instance, I progress very slowly in playing the piano because good progress requires two other principles that don’t “get along” with my principles above:
1. The “one more lap” principle. If you sat down, and got tired after an hour, you need to spend two more, and then you can get up.
2. The “clenched teeth – go” principle. If you’ve taken on learning something, do it regularly, preferably at the same time, and if necessary, through “I don’t want to”.
