Three days of Russian spidering

 kw: blogs, blogging, spider scanning

I checked in on my blog and found more than 4,000 hits in the past week, nearly all on July 28-30th. Looking at the "Audience" view I found the following:

Basically, subtract the Russian spider(s), and there were 289 "honest" hits, which is usual. It would be gratifying to have thousands of weekly views, genuine ones, but this just isn't that popular a blog.

Oh, well. Не топитесь в слезах от скуки.

Nature as healer

 kw: book reviews, nonfiction, nature, the natural world, lessons for living

The trend to divorce humanity from nature began long ago, with the Greek philosophers of the 400's BC or earlier. I remember reading that they preferred argument to experiment, sophistry to evidence, such that they could argue for hours about how many teeth a horse has, and nobody would suggest going to the nearest horse and looking in its mouth. That's probably a bit exaggerated. Curiously, the rise of experimental science (first called "natural philosophy") during the Enlightenment seems to have cemented the divorce, at least for a time.

In the recent generation or two increasing numbers of researchers and students have been willing to accept that we are part of nature. The "natural-artificial" divide is exaggerated at best, and flat wrong in most areas. It is true that human culture and technology have largely insulated us from many natural phenomena, but we see less efficacious technologies throughout the animal kingdom, in everything from bird nests to the tunnels of mice and hares, to bee hives and wasp nests, and to the tools apes and some birds use to winkle out termites and other insects to eat.

A side note: the just-delivered issue of Scientific American has, on its back page, a brief survey of the most numerous species of birds. The House Sparrow is the most numerous known wild bird, having a population estimated to be between 1 billion and 3 billion. A quick search for the numbers of mice yields an estimate of around 20 billion. There are also that many chickens and a billion swine (bonus results of the search), but those are domesticated, part of human culture; there would be far fewer of them if we weren't raising them. But this does indicate that, for our size, humans are much more numerous than we would be without our admittedly huge level of technology, even in the Third World.

It is good that at least some of us are getting more comfortable with being part of nature. The divorce from nature, almost exclusively in Western culture, has led to this quote, about the strain between proponents of the Enlightenment view and those who held back:

Those who balked at this epic drive to disenchant, who failed to champion the notion that there are eternal truths discernable, as Voltaire put it, by "anyone of good sense," were considered ignorant, underserving of respect of consideration. So should you ever wonder where hostility toward intellectuals comes from, or why educated white men have so often irritated the crap out of people from other backgrounds, the Enlightenment is a good place to start looking.

That is from page 55 of The Eight Master Lessons of Nature: What Nature Teaches Us About Living Well in the World, by Gary Ferguson. He has worked as a naturalist for the National Park Service, and writes about his experiences in this book, along with his interpretations of the lessons one can learn by spending more time in natural settings.

It is worthwhile for us to dwell on eight terms that I glean from his eight chapters:

Mystery, Connections, Diversity, Yin-Yang Balance, Zoomorphism, Efficiency, Resilience, and Memory (i.e. Mentoring)

I will dwell a moment on just three of these.

• Diversity is not just about racial balance in schools, cities, and workplaces. It is about variety versus sameness. A litter of kittens will have one or two that are bolder, another that is more skittish or shy; some will be affectionate pets and others more aloof. The intelligence of the womb ensures that at least a few of these cats will be well adapted to a changing world. A field of wildflowers of many colors is unlikely to be wiped out entirely by some sudden event such as a new disease or a giant storm: Even though some of the species in that field may be entirely destroyed, not all. We are happiest when we have learned to relate to people of different backgrounds. It is good to be "cosmopolitan". Excessive narrowness is unpleasant. I rejoice in having, among my closets friends and associates, people from a dozen nations and a half-dozen Western "subcultures."
• Yin-Yang Balance refers to the balance of masculine and feminine qualities, as traditionally understood. The Chinese Yin-Yang diagram is shown in several ways, with the dark section sometimes ascendant, the light section sometimes ascendant (more commonly), or with the sections side by side. I chose to put them all together, with the understanding that these are "clockwise" tadpoles, and a mirror image is equally possible. The "enlightened" suppression of any roles for women "outside house and home" is thankfully ending, but we still have a ways to go. Animals and plants cannot afford to suppress anything, for reasons expressed in the chapter on Efficiency. A man with no feminine attributes is as unpleasant as a woman with no masculine attributes. We each embrace both, even though each of us will emphasize them according to our nature and learning. More exposure to nature can help us learn to achieve a more harmonious balance.
• Zoomorphism is the opposite of Anthropomorphism. For a few hundred very unenlightened years, animals were treated as automatons, having only "instincts", and any evidences of pain or emotion were denigrated as "automatic responses." If we, at least those of us with a scientific bent, truly understand what Evolution means, we realize that our feelings and emotions and reactions descended from our animal ancestors along with the size of our bodies and the strength of our muscles. As a Cheyenne elder told the author, "We're the ones who took our qualities from the animals. It's never been the other way around." (p. 127) True science embraces this.

When you get down to it, we all feel better when we spend time in a natural setting. It is a rare person indeed who, taken into a field or forest, dashes back to a cubicle as though fleeing a monster. The author describes some chemicals in the air of a forest that may explain why taking a "forest bath" makes us feel so good. Chemicals or not, getting outside, even in a manicured yard, is better than spending all one's time locked away indoors. For myself, I know I must at least take a walk frequently; daily is best. I'd rather do that outside than do "mall walking" unless it is raining (and even then, if it isn't raining too hard…).

As much as the author has worked in the natural world, some glaring ignorances appear. On p. 76 he speaks of us sharing the planet with "more than a trillion species of plants, animals, insects, and microbes." The best current estimates of the number of species, including microbes, is between 100 million and 1 billion. Perhaps he was influenced by the understanding that each of us is host to tens of trillions of bacteria, primarily in our intestines. I am also not sure why he writes of 23 "universal proteins" in all life. There are 20 amino acids, which are used to make up all the millions of proteins found in living cells. The human genome is composed of 23 chromosomes, each of which consists of around a hundred million ACGT "letters". Again, perhaps two facts got mixed-and-matched in his mind.

The writing is lyrical and enjoyable. It becomes clear that the author is still processing the death of his first wife fifteen years ago. Having had significant losses in my own life, I understand that some things you don't get over, you just learn to live with the gap. I am thankful he has married again, happily.

Opening the ocean deeps

kw: book reviews, nonfiction, submersibles, deep ocean, expeditions

Josh Young has an explanation for what drives people like Victor Vescovo to extreme exploration: as many as eleven copies of a gene that affects sensitivity to dopamine, the "feel good" neurotransmitter. Most of us get along fine with two or three copies, and we may get a thrill from the occasional bit of risk-taking (like the pursuit of a friend and myself at age 13, of trying to go from one end of a block to another through back yards and not get caught). Those with genetically enhanced dopamine metabolism need stronger stuff.

Whether that is the explanation or not, Vescovo was driven, first to build a fortune of millions in various ventures, all the while spending substantial chunks of cash to complete the Explorers' Grand Slam, defined at the EGS website thus: "The Explorers Grand Slam or Adventurers Grand Slam is an adventurer's challenge to reach the North Pole, the South Pole and all of the Seven Summits." It takes a little more digging to find that "reaching" the Poles involves skiing at least the last hundred kilometers, even if you were taken there by aircraft, and that the Seven Summits are Everest, Kilimanjaro, Denali, Aconcagua, Vinson Massif (Antarctica), Elbrus, and Kosciuszko (Australia; later replaced by an Indonesian peak, the Carstensz Pyramid).

So there you are, fifty years old, and you've just completed the Grand Slam. Now what? There's plenty of life left in those old bones! Inspired by the challenge of the deep sea, Vescovo began almost immediately to add the Five Deeps to his accomplishments. As Josh Young writes in Expedition Deep Ocean: The First Descent to the Bottom of All Five of the World's Oceans, Victor Vescovo figured he could get a deep-diving submersible built for around $10 million or so, a tenth of his net worth at the time.

The actual cost came to more than twice that. Then the sub needed a tender, a ship and crew to take it from place to place and to launch and retrieve it. The submersible, built by Triton Submarines, was named Limiting Factor (LF), and the tender, a 225-foot craft, became Pressure Drop (PD). The ship needed extensive refitting. It had been a military craft, and upgrading it to commercial standards cost millions more. A state-of-the-art sonar system, so they could verify the depths reached, cost about another million, and three "landers", robotic, autonomous submersibles, cost $300,000 each. LF and PD and the landers were named for craft in the Culture novels by Iain M. Banks, a favorite series with Vescovo. The final cost of the construction, refitting, crewing, and expeditions was about $50 million.

In the picture above a portion of the pressure sphere and its portholes can be seen. The sphere is titanium, 59" in diameter (because of some international regulation), and weighs 8,000 lbs. From the size and weight I calculated that the wall thickness is 5.5". The sphere was certified in a testing chamber in Russia, the only one in the world that could test it to a pressure of 20,000 psi; the pressure at the Challenger Deep (Marianas Trench) is about 16,000 psi.

Much of the book relates the sturm und drang of getting the sub built and the tender refitted, plus the regulations and red tape Vescovo's team had to contend with, plus the friction that always develops when you have at least a dozen alpha males striving to work together. Much of the second half relates the year-long expedition to visit the Five Deeps (see more here). These, with their verified depths, are:

• Puerto Rico Trench, Atlantic Ocean, 8,376 m, 24,390 ft.
• South Sandwich Trench, Southern Ocean, 7,434 m, 24,390 ft.
• Java Trench, Indian Ocean, 7,192 m, 23,596 ft.
• Challenger Deep in Marianas Trench, Pacific Ocean, 10,925 m, 35,843 ft.
• Molloy Deep, Arctic Ocean, 5,551 m, 18,212 ft.

Of these, the Molloy Deep is the only one that is "shallower" than 6,000 m, the defined boundary of the Hadal Zone. Along the way, a few other deeps were plumbed, including the Sirena Deep, also in the Marianas Trench, at 10,714 m or 35,151 ft, which makes it the second-deepest Deep. Vescovo made at least one solo dive at each of the Five Deeps plus Sirena. He also made a solo dive to the wreck of the Titanic, and others made multiple dives at all locations.

A secondary function of the expedition was scientific, and a number of scientists were involved. So also were a couple of "tourists", including astronaut and game developer Richard Garriott, seen here with Vescovo inside LF. Garriott flew with ISS at his own expense ($30 million); I don't know if he self-funded his dive to the Challenger Deep, piloted by Vescovo.

Vescovo was one of a few pilots of LF, but when there was a celebrity to "take deep", such as Kathy Sullivan, the first woman to conduct a spacewalk and the now first woman to descend to the Challenger Deep, Vescovo piloted.

Triton and Vescovo were hoping the Triton Hadal Exploration System (LF plus PD) could be sold to a country, company, or consortium, but that has not yet occurred. Vescovo and his company Caladan Oceanic have conducted further explorations, typically with a more intense scientific component.

Although eating within LF is mentioned a few times, there is nothing about how toileting is handled in a sphere with an inside diameter of about four feet, further encumbered by oxygen tanks and other equipment, particularly with two occupants. If it were me (in my younger days, before my colon was shortened), a day or two of fasting, and abstaining from water for several hours before a twelve hour dive, would be needed. But I care for my creature comforts too much!

That's enough from me. It's a thrilling book, a great story well told.

A book for inquisitive children

 kw: book reviews, nonfiction, science, questions answered, compendia

We all know a youngster who asks "Why?" about almost everything. Sometimes they're just challenging a parent's decision, but other times the question is, "Why is the sky blue?", or, "Why do knuckles crack?"

Jay Ingram likes to answer questions…in detail. In Why Do Onions Make Me Cry: Answers to Everyday Science Questions You've Always Wanted to Ask (a follow-on to The Book of Why), he tackles 51 such questions, with answers ranging from two to five pages, plus each of the five sections of the book has a "History Mystery" such as "Did Newton really get hit on the head by an apple, inspiring his thoughts on gravity?" The length of the answers and their comprehensiveness indicate that Mr. Ingram knows you'll get follow-on Why's.

Some questions lead to others, sometime in interesting directions. In his answer to "Why is the sky blue?", he also digs into how the words for colors seem to have developed over time. "Blue" wasn't much of a concept long ago, possibly because other than the sky, not much is blue (flax flowers and certain butterflies, and that's about it), while purple was well known because purple dye is made from chemicals obtained from certain sea snails. Thus, blue things were called "purple" until truly blue dyes, such as woad, became economical to produce, while words for red, yellow and green arose very early. Color perception probably didn't change, but people's ideas about colors changed.

While we're in the blue sky area, look closely at this satellite photo. The bluish tint in the upper right area is from looking through the blue sky from above! The higher mountains don't have nearly so much air above them, and the color doesn't show.

This leads me to a question about blue skies that this book doesn't answer, and I'll dig into it as a bonus: 

Does every planet with an atmosphere have a blue sky?

The easy answer is No, because we have all seen recent pictures from Mars and the sky is pinkish. But there is an underlying complication. Mars has such a thin atmosphere that Rayleigh scattering, which makes the sky so blue on Earth, is a very, very small effect. The pinkish dust that is nearly always present in the air on Mars overwhelms the scattered blue light. On rare occasions, the wind on Mars calms enough for dust to settle, and the sky gets almost black, with just a bit of very deep blue. So let's refine the question: Does every planet have a blue sky when the air is very clear?

This gets into the colors of stars! We call the Sun a yellow star because we see it through our atmosphere, and 1/3 of its light is scattered by the air to make all that blueness. The light that gets straight to us is thus a pale yellow. From the International Space Station or any other orbiting craft, the Sun appears utterly white. This makes sense. Our eyes evolved to see "average daylight" as "white", and the color of the light that reaches a colorless object on Earth is direct sunlight plus blue light from the rest of the sky, and that adds back to the pale yellow to be white.

You might have heard or read about bluish and reddish stars. Most of the stars we see at night are a bit bluish compared to the Sun. The visible ones are bright, hot stars, and stars hotter than the Sun are bluer. A few stars, such as Betelgeuse in Orion and Antares in Scorpio, look reddish if you look carefully. Looking at one of these stars with slightly out-of-focus binoculars lets you see the rather orange color more clearly. They are redder than the Sun because they aren't as hot. However, they are still hotter than the filament in an incandescent light bulb, which actually emits a rather orange-colored light. Our color vision adapts to this and it looks "white enough" to us, unless we look at a lamp next to a well-lit window.

Suppose there is a planet orbiting one of those orange-colored stars. Would it have a blue sky? There are two answers to this. Firstly, to us, the star would look slightly more orange than the Sun does, and the sky, if very clear, would be "less orange", and probably would look pale blue. But Secondly, if there are creatures on that planet which evolved there, they to them their star looks white, and the sky would look blue! On a hotter star such as Sirius, which is already bluish, the sky above any planet would be a more intense blue than our sky, barring pink dust, of course.

Enjoy this book, and if you have kids that are full of questions, keep a copy on hand, so you'll have at least 50 questions that you can actually answer.

Before and after the Lensmen

 kw: book reviews, science fiction, space opera, story reviews

In my late teens and early twenties I read science fiction obsessively. So much so, the local library began buying more to meet the demand, though it was a "demand of one." Very early I read the Lensman novels by E.E. "Doc" Smith. The themes I remember are the Lens as an unforgeable authentication device; mental telepathy and other mental powers, first in the Arisians and later in the Lensmen; and the inertialess drive, which enabled space travel across the galaxy with the ease of crossing a county or state by automobile. The seven Lensman novels were published between 1948 and 1954.

I recently obtained the eBook The Space Opera Megapack, which contains two of Doc Smith's books in the form first published as serials. One is his first published novel, The Skylark of Space, published serially in Amazing Stories in 1928, where it got the cover illustration and his name highlighted (spelled out!), but his co-author Lee Hawkins Garby (who wrote the "love interest" parts) was not mentioned.

Skylark was published in 1946 as a hardcover, greatly edited, after other novels in the series had become popular; the Megapack version is the 1928 text.

It's funny. I've known about Skylark and its siblings for decades, but I don't remember reading any of them. I remember only the Lensman books. The space drive in Skylark, set in a thoroughly Newtonian universe, involves "release of binding energy" of the copper atom, facilitated by a newly-discovered element called "Metal X". Doc Smith had a dark view of human progress. The Military-Industrial Complex that President D.D. Eisenhower warned us about in the 1950's was already well advanced, and Smith expected it to worsen (Even he would be shocked at how bad is has become!). In the novel industrialists run things (as venally as possible), and the chemist-protagonist Dick Seaton has to covertly develop a spacecraft with the (expensive!) help of an honest industrialist, Martin Crane. It proves a success.

It's an engaging tale, though the social and romantic aspects are too saccharine for my taste. The riders of the Skylark find humans and near-humans on other planets they visit. Doc Smith thought of the Skylark books as "semi-science fiction". Indeed, if there were no relativity, no "speed of light limit", the energy needed to accelerate a huge spaceship to speeds many times that of light would require total annihilation of a mass greater than that of the spacecraft. A few hundred pounds of copper would hardly suffice.

The story suited the times. It is credited with setting off the entire genre of Space Opera, so its inclusion in the Space Opera compendium is entirely fitting.

The same volume includes Galaxy Primes, serialized in 1959 in Amazing, a very different story. Doc Smith wrote it with no co-author. The protagonists are "psionic Primes", with the highest order of mental abilities known on Earth (or Tellus, Smith's designation in most of his books). Two male Primes and two female Primes are put aboard a spacecraft with an experimental interstellar drive that is engaged by pushing a button. They push the button and find themselves so far from Tellus that no constellations can be recognized. There is a shorter-range drive, of an unknown type, for zooming around among planets in stellar systems. They eventually find out they are in a different galaxy!

The Primes find human life everywhere, plus Guardians who are semi-humanoid (4 arms and hatchet-shaped head), that oversee the human planets, to ends not discussed and thus secondary to the plot. Tellus has no Guardians (yet). The powers of the Primes using "Gunther" techniques, are godlike. There are lower-level psionic persons on most planets, and a few Primes scattered here and there.

The first part mainly involves the four Primes learning to get along and how they discover the way to control their interstellar drive. Once that is accomplished, they gather Primes from many other systems to form a pan-galactic organization, with ties to other galaxies. The distance the ship can jump depends on the power of the Prime who directs it, and only the leading Tellus Prime, Clee, and a few others, can jump galaxies.

Apparently Doc Smith wanted an Earth-grown version of the Arisians, and the novel investigates the implications of almost godlike humans. It's a fun read, though I don't imagine such powers being properly used by anyone until a few tens of thousands of years of moral development have occurred. We consistently misuse the feeble power we have…

Some of the other stories in the Megapack are quite good, but I found many others to be "barrel scrapings." Whatever it took to fill an eBook of 1,400 pages, of which I read about 3/4.

Will any lock ever be good enough?

kw: book reviews, nonfiction, cyberwar, computer hacking

A wag once said, "If we built houses the way we build software, the first woodpecker to come along could destroy civilization." I wrote software for forty years, and I must say, with some chagrin, that I agree.

Sandworm: A New Era of Cyberwar and the Hunt for the Kremlin's Most Dangerous Hackers, by Andy Greenberg makes it clear that the woodpeckers are winning. (To see a fictional forecast of a war with China that includes cyberwar, see the recent book 2034: A Novel of the Next World War, which I reviewed this past May.)

American security analysts use "Sandworm" to refer to the penchant the Russian hacking team initially had for Frank Herbert's Dune novels, as seen in names and comments in their code. Other security groups around the world have different monikers.

The book Sandworm is primarily a history of the damaging cyberwar carried out by this group, and apparently a few other allied groups, plus forays into cyberwar by others, including the US/Israeli team that launched Stuxnet to disable Iran's equipment for preparing bomb-grade uranium. By far the most beleaguered victim of the Sandworm hackers has been the Ukraine. Their computer-connected infrastructure, from electric utilities to the post office, has been attacked repeatedly, leading to blackouts and other disruptions. The author considers Ukraine the test bed for the Russian hackers.

One would think that the nations, or at least the NATO allies, would get together to create and invoke Geneva-Convention-styled measures to "outlaw" cyberwar carried out against civilian populations. When the author questioned a number of security leaders about this, however, the cynical response was that "we" don't want to hobble ourselves from using such measures.

I noticed that it was an American, Mike Assante, who first demonstrated, to Pentagon leaders and others, the capability to destroy a running powerhouse generator using software commands. It was also American (plus Israeli) software that was first used to destroy physical equipment, with the Stuxnet attack. I couldn't avoid the analogy with the first use of nuclear weapons, again by America. I don't like where this is going.

I am puzzled that, in the face of what is known about Russian cyberwar—going on right now—, and Western cyberwar capabilities, the American military seems hell bent on making all our weapons systems Internet-dependent and GPS-dependent. It's like giving a key to your house to "the mob."

About the time I was born the term "fail safe" appeared, and it enjoyed a few decades of popularity. Somehow, it was not much applied to software. Over time, it was changed to "failsafe", and the term is becoming current again, but it did not appear in Sandworm. I don't know how "popular" it is in the Pentagon. One would think that system robustness would be a top priority, particularly for the American military with billions at their disposal. Utilities and others need failsafe systems also, even though their budgets are tiny by comparison.

Bottom Line: All the test cases have been tested, by the Sandworm folks and others. Every red line has been crossed. Software bombs have already been emplaced, almost anywhere a security analyst cares to look. When will the triggers be pulled? It apparently isn't up to us. Fat, Dumb & Happy, that's what we are, with a target front and center on our T-shirts. Not a good feeling.

History hidden in chair seats

kw: historical investigations, upholstery, side chairs, photo essays

When my wife and I were married we bought a set of four side chairs and a small dining table at a thrift store. After we bought a house we bought another set of five chairs, four side chairs and one with arms, and a better table (still at a thrift store); we gave the old table away. Soon after that a relative sent us an antique table with its own set of five matching lyreback chairs, one of them having arms. We gave away the thrift store table, and now we could have big dinners!

The original four chairs had some kind of whitish plastic on the seats, and both sets of the others had patterned fabric seats. All were looking quite worn. We bought several yards of a darkish teal-colored upholstery fabric and I reupholstered all of them. I left the plastic on the original set—I just covered it—but I stripped and replaced the fabrics from the other ten chairs. For those ten I also added a half inch more padding of "fiberfill" to match the thicker padding on the first four.

About thirty years later the teal fabric had done its duty and it was getting tattered, so we bought a patterned blue-and-tan fabric, getting enough so I could center the pattern on each seat, as this photo shows. However, this is a less durable fabric, and fifteen years of use left the chairs in the condition shown here.

We decided to reupholster them again, a third time. We had long since moved all the lyreback chairs to bedrooms where they'd get less use because the backs are fragile, so their seats are in good condition. We decided to redo only eight of the nine original chairs, leaving the chair with arms alone. The new fabric will be seen later on. We also decided to add a couple of inches of foam. As we've aged, the chairs have begun feeling a little too stiff for us.

You can see above that one set of chairs—the first set we bought—is oak with a walnut stain, and the other is of a lighter-colored wood, probably maple. The lyreback chairs are cherry with a walnut stain.

Turning the chairs over we can see the makers' marks. The oak chairs were made by Richardson, but which of the many companies by that name, I don't know. At least three companies by that name, in different states, use an "R" logo similar to the capital "R" in this mark. One of the companies, in Arizona, was founded in 1972, while these chairs were decades old when I bought them in 1976, so we can rule that company out.

Morris Furniture Manufacturing Co. of Los Angeles is less of a mystery. This is not the Phyllis Morris company, which seems to have specialized in fancy, ornate beds for celebrities, founded in 1952, but a different company that was founded in 1936, so there is plenty of room for the maple chairs to be from the 1960's or earlier, perhaps much earlier.

As I mentioned, the oak chairs still had the plastic covers under the upholstery I'd used before. This time I decided to remove it to see what was underneath. It was this action that triggered the historical adventure.

When I removed the plastic and cleaned it, I found it is Naugahyde, and that it was not the original seat cover. It was held on with tiny tacks, ¼" long (7mm). Underneath I found staples from an earlier event, apparently the original cover attachment, which had bits of greenish, patterned plastic remaining as though whoever put on the Naugahyde just ripped the plastic off and nailed over it.

This is the collection of little tacks I removed from the four oak chairs. There is one larger tack, that had apparently been used to hold a corner where several layers needed to be held. I found only the one.

The picture below shows what I found under the Naugahyde.

The staples left behind frequently held a small bit of greenish-gray plastic. Two of the chairs also had the torn edge of the label; you know, the one that says, "Not to be removed under penalty of law." The bits of remaining text indicate that the chairs were made after 1929, but not how much later. They are probably from the 1940's or even a little later.

After I took the Naugahyde from the first chair, my wife and I discussed what to do. We decided to replace the Naugahyde as a foundation for the added padding.

Before going on I'll show what the older staples looked like, compared to the ones I used for this work.

The old staples are quite robust. You can see from the dents in the wood nearby that they were inserted with a lot of force, so I infer that a powered staple gun was used. Such tools were invented in the early 1950's, so that puts an age limit on the oak chairs.

The scattering of holes along the edge were made by the little tacks, which were clearly put in by hand. Someone with good aim can use a magnetized tack hammer to hold the tack and drive it in, right next to the thumb holding the fabric! Missing is even more painful than simply hitting the thumb with a hammer.

The way the Naugahyde was cut in an in-and-out way near the tacks indicates that it was first pulled taut, then the tacks were put in, after which it was cut closer to the tacks. That reduced the need for such excellent aim.

Once we decided to keep the Naugahyde in place, I put it back on the first chair with staples.

My initial process for the oak chairs was this: 

1. Remove the blue-and-tan fabric.
2. Remove the tacks holding the Naugahyde, along one edge.
3. Staple that edge back into place.
4. Continue with all edges. These chairs have a curved back to the seat, so they had to be attached a little at a time along the curve.
5. Use a felt tip marker to indicate where the screws go (illustration later).

To get the maple chairs to this point, I just had to remove the blue-and-tan fabric. To explain what I had to do to measure the new fabric, I need this picture:

The padding we used was cut from a Queen size mattress topper. Each chair was to be padded with two thicknesses. To partially compress it while attaching the fabric, I gathered weights from our various workout spaces to total 40 lbs (18 kg).

At the bottom we see the wrong side of the new fabric, the two thicknesses of "eggcrate" foam, back to back (I used the chair bottom as a template), then the chair bottom, and the weights on top.

To get the fabric the right size I laid out a large piece of newsprint in place of the fabric shown here, drew it up to about two inches inside the edge of the chair bottom, and marked it. I made separate templates, because the two kinds of chair have quite different seat sizes and shapes. The templates were used to cut the fabric, laid out in our spare bedroom, using a drywall square under the cut line to keep the scissors from harming the carpet.

At the point in the process shown above, I cut the curve by eye. I also removed a square of fabric from each corner (two per chair for the oak chairs, and four per chair for the maple chairs later), to reduce bulk in the overlap areas.

Right after I made the photo above, I cut the curve from the lower part of the fabric, and stapled it into place.

Once that was done I measured the hole-to-hole spacing in the chair support, to refine the felt tip marker lines, such as those seen here. In this corner, and in about half the others, repeated removal-and-replacement had resulted in a real mess. I cleaned out the holes. Then I carved bits of wood and glued them in, and used a rotary tool with a sanding wheel to flatten them after the glue dried. I used Elmer's Wood Glue. When each repaired screw location was ready, I marked the location and drilled a 1/8 inch pilot hole.

I should mention a detail about stapling the fabric to the plywood. I had cut enough extra so I could fold about an inch under; thus there is not a cut edge showing. I used 5/16 inch staples rather than 1/4 inch so the extra thickness would not be a liability.

Here is the first of the oak chairs to be reupholstered next to one that is ready to be done.

We like the darker fabric color and denser pattern. It won't show spills nearly as badly as our prior fabrics.

This chair design is also quite a bit more robust than that of the maple chairs. I have not had to knock any of these apart and re-glue the joints, while all of the maple chairs have needed such attention.

Here is the first of the maple chairs to be reupholstered next to one that is ready to be done.

Here you can also see the nice woodwork of the backs. We like these chairs, even though I prefer not to sit in them because I am twice as heavy as my wife and I tend to loosen their joints. You can see a hint of the problem in the crossbars that just show below the seats. This post from 2018 shows one of these getting reglued.

Now that all eight chairs have been redone, we have prettier, more comfortable seating for the dining room, the room we use the most.