Sunday, October 9, 2016

Credit Where Credit is Due

You know, as much as I despise Donald Trump, I have to admit he's using this latest scandal for the benefit of the community.

Trump Grabs some Pussy

Saturday, October 1, 2016

Early Aircraft as Tools of War

Last month, we examined the earliest attempts at unpowered flight, and saw humanity as a fledgling bird, taking its first uncertain hops into the glorious skies above. Now we'll explore the next logical step: using the skies to kill people.

We already touched on this in the previous article, where we learned that the first documented use of the Kongming lantern was to frighten enemy troops, and that early kites were employed in military signaling and propaganda. But what about balloons big enough to lift a person?

My Balloon Against the World

In Europe, as in China, military applications soon followed the invention of flying machines. In 1796, just ten years after the first recorded flight of a manned balloon, the French Revolutionary Army found itself outmatched and outnumbered. France was at war with a coalition consisting of Prussia, Austria, Great Britain, Spain, Sardinia, Naples, the Dutch Republic, Ducklovia, Gondor, the Romulans, and I think probably Chuck Norris. The French National Convention's first response was… well, it was probably to shit their pants. But the second response was to institute the levée en masse, conscripting all able bodied men aged 18-25 into military service and ushering in a new era of total war in Europe.

Captain Coutelle at the battle of Fleurus
Captain Coutelle at the battle of Fleurus
But it wasn’t enough to simply have more men on the field, so the Revolutionary Army looked for new tactics and new ideas. Among these was the Compagnie D'Aerostiers, or Company of Balloonists. The advantage offered by aerial warfare, however, was not recognized by everyone. Upon arriving at the front with his balloon, Captain Jean Marie-Joseph Coutelle was stopped by a superior officer and nearly shot as a "suspicious character" for his wild notion of ascending above the battlefield in a balloon[1] .

Despite this skepticism, Coutelle made a good account of himself, observing Austrian troop movements through a telescope from his balloon, and relaying the information via signal flag to officers below. Not only did this allow the French to match their enemy's maneuvers, move for move, but it had a significant effect on morale, assuring the French that their foe could hold no surprises for them. The very presence of the French balloon likewise sowed worry among the Austrians, who only had to look up to see that they were under constant observation[2] .

Blow Them Up to Blow Them Up

The use of balloons as observation platforms was now established, but their use as an offensive weapon would not come for another half a century. Oddly enough, it was Austria—first to suffer the effects of aerial observation—who would pioneer aerial bombardment. Its target was Venice, which had been acquired by Austria as part of an exchange of territories at the end of the War of the First Coalition in 1797, just a year after Captain Coutelle first took to the skies above a battlefield. But by 1848, Venetians were sick and tired of Austrian mismanagement, and they rebelled.

Venice balloon attack, 1849
Venice balloon attack, 1849
Venice has historically been a tough nut to crack for besieging armies, due to the natural protection afforded by the Venetian Lagoon. The Austrians found it no different, and struggled to get a foothold in the rebellious city. So they bombed it. Of the 60,000 artillery rounds aimed at the city, most were fired from gunboats or batteries on shore[3] [4] , but a few explosive shells were dropped by balloon.

William Henry Stiles, an American diplomat stationed in Vienna at the time, describes an early test on June 24th, 1848. Stiles's secondhand account says that these first balloons were launched trailing a long length of copper wire, which attached to a galvanic battery on the ground. When the balloons were positioned over their target, an electrical signal dropped the bomb and lit its fuse, so that it exploded approximately when it hit the ground. Stiles's report is a little sketchy, seeing how far away from the action he was, but there's no doubt that these early tests were unsuccessful. He reports that all of the bombs fell into the water[5] , while other sources are notably silent about any balloon-borne terror from above on that date.

Franz von Uchatius, the actual inventor of the bomb-balloons in question, provides an account of a more refined attempt, made on July 15th. This time the balloons were launched by steamship, there was no battery, and the balloons seem to have been untethered. The explosive shells from the previous test seem to have been swapped out for shrapnel shells—gunpowder impregnated with lead bullets. They were detonated by timed fuses, which had to be set precisely to ensure they detonated once the wind currents had taken them over the city[6] . Uchatius called this attack a great success, writing gleefully of the "extreme terror and the morale effect produced on the inhabitants." Setting aside his air of mordenfreude, Uchatius' claim is dubious at best, because shrapnel shells cannot achieve their full lethal effect without the velocity gained from being shot from a cannon[7] , and because no one ever bothered to repeat the operation.

[Bad Pun] and Lowe

But, while balloons had failed their first use as offensive weapons, they retained their utility in observation, which brings us to the American Civil War and Thaddeus Lowe. Lowe had long been interested in lighter-than-air craft, and on April 19, 1861—five days after the start of hostilities at Fort Sumter—he took off from Cincinnati in an attempt to fly by balloon to New York. The weather gods were not on his side, however, and the wind carried him instead to South Carolina, where the first people he encountered assumed he'd been sent from the devil[8] . On a more personal note, I've been to South Carolina and they thought I was sent by the devil, too.

Lowe's portable hydrogen generators filling the observation balloon Intrepid.
Lowe's portable hydrogen generators filling the observation balloon Intrepid.
Lowe's exploits reached Lincoln, and he was called upon to form the Union Army Balloon Corps, to provide observations of enemy movement, report on the fall of cannon shot, and assist in mapmaking. Information could be instantly communicated to commanders below, by telegraph wire or signal flags. Lowe developed portable hydrogen generators carried by wagons, allowing balloons to be carried anywhere and inflated on site. He even employed the first aircraft carrier, when he launched a balloon from a converted coal barge[9] .

Aerial observation was valued by the men on the ground, and even by some of their commanding officers. At The Battle of Seven Pines, his aerial observations turned what could have been a disaster into a mere quagmire. Among other observations, he noted the advance of Confederate forces encircling General Samual Heintzelman's detached force, and so saved it from annihilation[10] . This was quite fitting, as Heintzelman was an admirer of the balloon's use in warfare. Earlier in the campaign, he'd even gone up himself, observing Confederate defenses at Yorktown from one of Lowe's balloons[11] .

Observation balloon launched from coal barge.
Observation balloon launched from coal barge.
Despite this, the army's administrative staff was no friend to the Balloon Corps. Lowe provided his services as a civilian contractor, which alone bred disrespect from army officers, as well as resentment over the high pay he received for his specialist services. After Seven Pines, he was laid low by a bout of malaria and he returned to service to find that his equipment had been taken by the office of the quartermaster[12] . The gutted Balloon Corps was juggled from the Topographic Engineers to the Army Quartermaster office to the Corps of Engineers[13] , where a final insult was inflicted by cutting Lowe's pay by 40%. He resigned shortly after[14] , and his Balloon Corps languished before finally being disbanded.

But the American Civil War had not finished making its mark on aeronautics. In August of 1863, months after he lost his job due to the termination of the Balloon Corps, German immigrant and balloon pilot John Steiner ran into a military observer visiting from Germany. The observer was staying at a hotel just across the street from where Steiner had his personal balloon tethered, and Steiner offered to take him up in it. Suspended above Minnesota, the two discussed the limitations of a balloon, and the possibility of overcoming them by making a steerable airship. Steiner suggested an aerodynamic design: a cigar-shaped envelope with a rudder at the back.

And who was this mystery passenger that Steiner discussed his radical idea with? A snot-nosed 25-year-old first lieutenant by the name of Ferdinand Adolf August Heinrich Graf von Zeppelin[15] .

For Want of a Mail

Paris Balloon Mail, 1870
Paris Balloon Mail, 1870
The next great adventure in military ballooning would come from Paris. In 1870, nearly a century after it saw the first manned balloon flights ever recorded, the city found itself encircled by Prussian forces, with no way to get a message out by land.

Enter, the post office.

You didn't think that's where this was going, did you? It may seem absurd, but in the midst of a war that threatened to tear France apart, amid famine and siege, it was the post office that stood determined to maintain contact with the outside world, so that it could continue to deliver the mail[16] . Scoff all you want, but let's see what you do when you may have already won ten million dollars, and the Prussian army is stopping you from returning the reply card.

Inside the besieged city, pilots were trained, silk was commandeered, and balloons were constructed by seamstresses in idle railway stations. In all, 66 balloons were launched and 64 landed safely, the other two being blown out to sea. Each balloon could carry hundreds of pounds of letters—military and civilian—and the occasional officer hoping to muster a relief force from the countryside. Homing pigeons carried microfilm letters back into Paris, which were then recopied and delivered, allowing the mail to run in both directions. Over the course of the siege, balloon-mail carried two and a half million letters, 400 pigeons, and 102 passengers[17] .

Balloon construction in a Paris railway station.
Balloon construction in a Paris railway station.
Paris ultimately succumbed to the siege, but the Prussians were duly impressed by the shocking efficiency of the first air mail service. In 1874, German postmaster Heinrich von Stephan reminisced about it in a speech to the Berlin Science Society, and argued for a global system of mail and personal transportation by air. Among those who were inspired by a transcript of his speech? A worldly, 35-year-old Count by the name of Ferdinand Adolf August Heinrich Graf von Zeppelin[18] .

By Fire, Wire, and Cricket

At the turn of the next century, the dirigible airship would join the balloon in the role of military observation, and in World War I the airplane became master of the skies. But even in World War I, the balloon had a vital role in aerial observation. A tethered balloon could communicate by telegraph wire with an efficiency matched only by airships carrying expensive, finicky wireless sets. This made the balloon the preferred platform for reporting on the fall of artillery shells, which by that time were routinely fired from beyond the visual range of their gunners[19] .
World War II saw continued balloon use, both as observation platforms and as weapons. Everyone already knows about Britain's barrage balloons, lofted in the hope that Luftwaffe aircraft would either be damaged by their steel tethers or avoid areas with barrage balloons altogether. And of course there's Japan's incendiary balloons, sent over the Pacific on high altitude wind currents to attack mainland America.

Lesser known, but perhaps of more military significance than either, was Britain's Operation Outward. Outward involved nearly a hundred thousand hydrogen balloons, each fitted with either an incendiary device or a ground-trailing steel wire intended to short out high voltage power lines. Launched from Britain, they were carried by the wind across the North Sea and into Germany. The plan was not popular among the RAF, who were nervous about collisions between Outward balloons and their own aircraft[20] , nor among the Board of Admiralty, where one official complained that, "attacks of this nature should not be originated from a cricketing country[21] ."

Due to the above-mentioned RAF worries, the balloons were only released during daylight hours, despite fears from Operation Outward planners that daylight balloon attacks could be intercepted more easily. They were right, but even this proved to be a blessing in disguise. The Luftwaffe sent up fighters to intercept the balloons, costing fuel they could ill-afford to waste, and causing wear on their aircraft. So, because the balloons were so cheap to manufacture, at only two pounds sterling each, they could benefit the war effort even if none of them got through German defenses.

Operation Outward Launch Party
Operation Outward Launch Party. Photo from the UK National Archives, used under OGL.
Notwithstanding the objections of Lord Pishposh-and-Cricket, Outward was a great success. The balloons shorted power grids, started forest fires, and in one case damaged a circuit breaker at the Böhlen power plant—setting off a chain reaction that ultimately destroyed the entire facility and knocked 250 megawatts of German electrical generating capacity out of commission[22] .

Another bonus came from within the Nazi party, where a high-level party member designed a special clamp for use on high voltage lines, that was meant to minimize damage from wire-trailing balloons by disconnecting the transmission lines. Unfortunately for German power grids, the new clamp also disconnected during ice storms or high winds. But because the inventor was politically well-connected, the new clamps stayed in service long after they were proven counter-productive[23] .

Even when it wasn't wrecking Germany's shit by direct and indirect means, the operation forced the German government to divert manpower to repair crews, which had to remain on standby for repairing damaged infrastructure, and so couldn't be used for war production. Operation Outward, by comparison, used very little manpower at all. In fact, what it mostly used was womanpower. Whaaaaaaat? You mean to say that a lady can launch a balloon? Lord Pishposh would be flabbergasted. But yes, 140 personnel from the Women's Royal Naval Service served as the bulk of the workforce, launching 1000 balloons per day[24] .

And so we see that Hitler fell for both of the two classic blunders. The first, of course, is to never get involved in a land war in Asia, but the second and only slightly less well-known is this: never go in against a chick with a balloon when death is on the line.

For further reading, check out the references listed below. And if your interest is piqued by ladies in the lighter-than-air business, I recommend David D. Levine's excellent Arabella of Mars, which takes an age-of-sail adventure that would do Patrick O'Brian proud, and places it in a classic sci-fi setting akin to Edgar Rice Burroughs's Barsoom series.

 [1]Payne, Lighter than Air, 15

 [2]Payne, Lighter than Air, 16

 [4]Stiles, Austria in 1848-49, Volume 1, 332-333

 [5]Stiles, Austria in 1848-49, Volume 1, 333-334



 [8]Payne, Lighter Than Air, 16-17





 [13]Payne, Lighter Than Air, 18


 [15]Hallion, Taking Flight, 94

 [16]Allaz, History of Air Cargo and Airmail, 16

 [17]Payne, Lighter Than Air, 19

 [18]De Syon, Zeppelin!, 15







Thursday, September 29, 2016

Review: Borderline by Mishell Baker

You know, I usually hate books about the film industry. In my personal hierarchy of literary sins, they rank right below books about tortured writers. I mention this so you'll understand where I'm coming from, when I say that Borderline is one of the best books I've read this year.

Mishell Baker starts with a backdrop that I've just had it up to here with, but presents it in a way that's fresh and interesting. Not just by giving us an L.A. that's swimming with fae-folk, and not just by tying them into filmmaking in a delightful way, but by letting us see this world from a rarely-seen point of view.

The protagonist, Millie, is a borderline, double amputee, suicide attempt survivor with severe facial scarring, a penchant for impulsive behavior, and a wry sense of humor. This is such a welcome relief from the typical L.A. protagonist, whose most pronounced character trait is usually a vague sense of ennui. But Millie has grit, and spunk, and if she ever ran into that typical L.A. protagonist, I'm pretty sure she'd kick his ass on general principle. I believe she could do it, too, with or without her prosthetics.

I may be wandering from the point, however. This is a fantastic book. The writing is beautiful, the dialogue is crisp, the plot is twisty and interesting, and the characters are believable. I love it, and I can't wait for the next book in the series.

Thursday, September 1, 2016

History of Flight: Unpowered Flight

If you had to guess where would you say the first lighter-than-air craft was invented?

If you said China, you're either-well versed in history or you know how to game a short-answer test. Because, let's be honest here, the Chinese have invented 90% of everything. If you're ever on Jeopardy and the hint starts with, "The first place to invent…" Don't even read the rest of the question. Just buzz in and say, "What is China?"

First in Flight

Kongming Sky Lanterns
CC Takeaway via Wikimedia Commons
First documented in the 3rd century CE, the sky lantern is a hot-air balloon with an envelope made of paper and a fire slung underneath. Its invention is usually credited to Zhuge Liang, a military strategist of the Three Kingdoms period, and to this day is also called by his courtesy name, Kongming. Originally used as a psychological weapon to spook the hell out of enemy troops,[1]  Kongming lanterns were later used for military signaling, and by civilians during Mid-Autumn and Spring Festivals,[2] to create a festive river of light rising thousands of feet into the air.

Europe would not replicate this technology until 1709, when Bartolomeu de Gusmão flew a paper balloon of the same basic design as the Kongming lantern to a height of 12 feet[3] . De Gusmão is thus regarded, by several sources I discovered while researching this article, as the man who proved that hot air can buoy up a lighter-than-air craft. Yeah, nice try. You've proven that hot air can buoy up more than just balloons.

And while we're on the subject, do you know where the first heavier-than-air craft was invented? Yeah, that was China, too. That aircraft is the kite, invented in China in the sixth century CE, if not earlier[4] . Like the sky lantern, the kite was not just a plaything, but an instrument of war. They could be used by city garrisons to send signals to friendly forces during sieges, or by military units who were cut off and unable to communicate their predicament by any other means[5] . They could be flown over enemy walls, and the length of the string used to calculate the distance that sappers should dig to, in order to undermine the defenses[6] . They were even used in psyops operations. Propaganda messages were written directly onto the paper of the kites, which were flown up and over enemy lines, then dropped by cutting the strings[7] . In civilian use, kites were employed in an aerial form of long-line fishing, in which a line and hook could be suspended from the kite, well away from the shadow of the boat[8] .

But surely the first human being to fly was Orville Wright? Or, if not him, then Jean-François Pilâtre de Rozier, the first man to ascend in a tethered hot air balloon in 1783?

Go Fly a Kite - Yuan Huangtou EditionSo, do you remember what I said earlier about buzzing in quickly if you're ever on Jeopardy? Yeah. The first documented human being to achieve flight was Yuan Huangtou, the son of a deposed Chinese emperor, in the 6th century CE. It wasn't as auspicious an event as you might be imagining, however. Guinness wasn't there, for one thing, and Yuan Huangtou was a prisoner of Gao Yang, a man who combined the traits of a scientific tinkerer with those of a true psychopath. Yuan Huangtou and other prisoners were tied to kites and thrown off the Tower of the Golden Phoenix in Ye. Alone among these unwilling pioneers of aeronautics, his kite actually flew, traveling a distance of two and a half kilometers before landing safely[9] . Compare this to Orville Wright's famous flight, which covered a paltry 37 meters, though of course Orville's flight had the distinction of being both powered and voluntary.

There are even stories of Lu Ban inventing a kite capable of lifting a man into the air as early as the 5th century BCE, for surveillance or as a platform for archery[10] . Historians usually regard these stories as exaggerations of Lu Ban's achievements, if not outright apocrypha, but the idea isn't as absurd as it may seem. 19th century inventors, Samuel Franklin Cody most famous among them, revisited the concept by building war kites that could lift not just one but several observers up to altitudes of thousands of feet, for as long as the wind remained steady. Many of these kites were made from nothing more than hemp, silk, cotton, and bamboo—all materials that were available in China in the 5th century. Which is to say, it's unlikely but not inconceivable that Lu Ban beat Cody to the punch by two and a half millennia.

Europe Discovers Finally Figures Out Flight

But whoever may have first invented the manned kite, credit for the first manned balloon goes to the Montgolfier brothers, Joseph and Etienne, of France. The Montgolfiers were paper manufacturers, because it just keep coming back to paper, doesn't it? Say, who was it that invented paper, again? I don't know, probably some white dude, right?

ANYWAY. The Montgolfiers got their start in the business of flight by experimenting with paper balloons and various buoyant substances. They first tried steam, but found that steam and a paper balloon don't go together super well. Then, learning of Henry Cavendish's experiments with hydrogen—then called "inflammable air"—they tried to fill their paper balloons with that. It didn't work, the hydrogen leaking out too quickly to provide buoyancy, but at least they didn't blow themselves up[11], so let's file that under "blessing in disguise."

Their breakthrough came in 1782, when Joseph noticed flecks of ash rising up a chimney. Believing that the smoke from the fire was permeated with a heretofore unknown type of buoyant gas, he named it Montgolfier Gas[12] . Personally, I would have gone with "De Gusmão, No Wait I Meant Zhuge Liang or, Oh I Don't Know, Maybe About Three Hundred Million Chinese People With Sky Lanterns Gas," but I guess that wasn't catchy enough. By any other name, however, the brothers had a solid foundation on which to build ever-larger hot air balloons. In tests conducted in 1782 and 1783, they lofted unmanned paper balloons of up to 20,000 cubic feet, reaching estimated heights of over a mile.[13] 

In a classic case of snobbery being the mother of invention, the French Academy was pissed that a couple of paper mongers had beaten them to a lighter-than-air balloon, and so commissioned Jacques Charles to duplicate the Montgolfier brothers' creation. Charles was confident of success, though it turned out he didn't have a clue how the brothers' balloon operated. He planned to buoy his own balloon with Cavendish's inflammable air, and lucky for him, paper was not a politically acceptable envelope material. Instead, he outsourced the job to brothers Marie-Noel and Anne-Jean Robert, who had developed a means of coating silk with rubber to make a tough material that retained hydrogen gas for long enough to loft a balloon.

It worked, and the test balloon ascended three thousand feet above Paris before drifting away and coming to a landing in the village of Gonesse. There, believing it had come from the devil, the villagers attacked the balloon with pitchforks, flails, and at least one firearm, before tying it to a horse and dragging it across the countryside[14] .
Montgolfier Balloon Being Assaulted by Peasants in Gonesse
From Astra Castra: Experiments and Adventures in the Atmosphere

So, do I even need to point out that there are no recorded cases of Chinese villagers committing aggravated assault against a Kongming lantern? No? Okay then, let's move on.

The aerial competition between the Montgolfiers and Jacques Charles was now on. The Montgolfiers came back strong, lofting living passengers aboard a flying machine for the first time in European history in September of 1783. Those passengers were a sheep, a duck, and a rooster. In the presence of King Louis, they were sent up in a wicker basket slung under a balloon decorated with the royal arms. The animals came down intact from an estimated height about 1,700 feet, confirming that life could survive at the lofty altitude of… well, a smallish hill. Seriously though, some scientists doubted that[15] .

First Manned Flight (Subcategory: Voluntary)

With those naysayers out of the way, the race was on to take a person into the air. Again, the Montgolfiers were first in Europe. That is, they were the first to build a balloon that could do it. They weren't the first to go up in it—are you crazy? They sent some snot-nosed kid up ahead of them, and so Jean-François Pilâtre de Rozier made the first tethered flight, less than a month after the concept was proven on a sheep[16] .
Montgolfier Hot Air Balloon Tethered Flight

Another month saw another breakthrough from the Montgolfiers: sending not just one but two poor bastards up in a balloon, and cutting the cord. It was Rozier again, joined this time by Marquis François-Laurent d'Arlandes. The Marquis was a last minute substitution, by order of the king. Louis had actually wanted condemned criminals to be the first to make an untethered flight, but Rozier wasn't hearing it. He talked to the Marquis, who talked Louis out of robbing Rozier of his glory. Louis agreed, with one condition: that the Marquis accompany him. Because even kings have a sense of humor.

The aeronauts rode on a wicker balcony surrounding a brazier on the underside of the balloon. They carried a supply of straw, which they were supposed to steadily feed onto the fire, though the Marquis was distracted by the sights passing below and had to be continually reminded of his task. He was also somewhat distracted when the balloon caught fire. No bigs, though. He spotted it in time and put it out with a wet sponge. If he hadn't been quite so on the ball, they would have come down in a flaming wreck onto the rooftops of Paris.[17]  As it was, they crossed the Seine and came down safely on the opposite side of the city.

Late but not to be outdone, the Robert brothers replicated the feat ten days later, sending Nicolas-Louis Robert—the elder brother—and Jacques Charles up in a hydrogen balloon. With no need for a brazier, their balloon featured a boat-shaped gondola, beating the Montgolfiers on style by a wide margin. They also beat them on duration, staying up two hours where the first untethered flight of the Montgolfier balloon—depending as it did on a continuous supply of fuel to stay aloft—only lasted half an hour.

Ebullient at the achievement, Charles stayed aboard after they'd landed. Once the elder Robert disemballooned, he signaled the ground crew to let go and went back into the air. Which was rather poor judgement on his part, since he hadn't considered the reduction in ballast from his departing co-pilot. He shot up to 10,000 feet so quickly that he saw the sunset twice in one day: once from the ground and again from aloft, having risen to an altitude where it hadn't yet gone down. As cool as this may sound, I wouldn't try it at home. Charles certainly didn't recommend it. He described an excruciating pain in one ear, and vented hydrogen to bring himself back down[18] . After that little misadventure, he never flew again[19] .

The Sky Conquered

At the beginning of 1782, the lighter-than-air balloon was a festive tradition and niche tool of military signalling, so unknown in Europe that Joseph Montgolfier thought he'd discovered hot air and tried to name it after himself. By the end of 1782, a human being had gone to 10,000 feet and returned safely to Earth.

The years to come would see even greater feats. In 1784, the balloonist Jean-Pierre Blanchard flew a distance of 70 miles. In 1785, he crossed the English Channel[20] . The age of the aeronaut had arrived, opening up a literal new dimension in human endeavors. The question, "Will Man ever fly?" had been resoundingly answered.

The only question that remained was, "So, uh, how do we use this to kill each other?"

We'll see how it was answered in the next article.

For further reading, check out the references listed below. I also recommend Ken Liu's phenomenal The Grace of Kings, which incorporates many of the above inventions into an epic fantasy setting.

 [1]Yinke Deng, Ancient Chinese Inventions, 131-132


 [3]Anderson, Flight and Motion, 120

 [4]Needhan, Volume 4, Part 2, 577.

 [5]Needhan, Volume 4, Part 2, 577.

 [6]Needhan, Volume 4, Part 2, 577

 [7]Needhan, Volume 4, Part 2, 577.

 [8]Needhan, Volume 4, Part 2, 576.

 [9]Needhan, Volume 4, Part 2, 588-589

 [10]Needhan, Volume 4, Part 2, 573.

 [11]Payne, Lighter than Air, 1-2


 [13]Collier, The Airship, 16

 [14]Payne, Lighter than Air, 3

 [15]Payne, Lighter than Air, 4.

 [16]Payne, Lighter than Air, 4.

 [17]Payne, Lighter than Air, 6-7.

 [18]Collier, The Airship, 20

 [19]Payne, Lighter Than Air, 10

 [20]Collier, The Airship, 20