The File From Under the Roof
The Bureau’s Paris desk has kept a file open since April on an expedition that no ministry, academy or observatory in France has any record of. Our correspondent, a gentleman of the rue du Cherche-Midi who signs himself only as the Executor of the Attic, sent five things and asked for nothing except that we print them. There is a bound manuscript diary, in a hand he states is the Emperor’s. There is a coloured plate of a vessel named Le Vaisseau de la Lune. There is an account of how it was paid for. There is a narrative of a landing, dated to the autumn of 1804. And there is a tobacco tin containing eleven grey pebbles.
The Bureau prints the substance of all five below and sets each against the record, as is its practice. It should be said at the outset that the vessel is the least of it. The vessel is merely the first objection, and the one disposed of quickest. The gravest is a single number, and the number is eleven thousand one hundred and eighty-six metres in a second — the escape velocity at the surface of the Earth, twenty-five thousand and twenty miles in the hour, which a body given no further push must already be making before it can be said to be leaving. Everything else in the file stands downstream of that figure.
Nothing in the file is dated later than 1806. A good deal of what is in it had not been thought of before 1865.
The Vessel, As Drawn
The plate is much the best-executed thing in the file, and it is the thing that gives the file away. A riveted iron cylinder with a conical nose stands on four splayed legs bedded on brass pads; there are portholes with heavy rims, a hatch, a ladder lashed to the flank, a boiler squatting under the skirt with copper pipes coiled about it, and two tricolours on poles. The workmen put the whole at some eleven metres. It is a handsome object, and it is the wrong object.
Begin with what it is not. France holds the oldest and best claim in Europe to the voyage as a literary form: Cyrano de Bergerac, published posthumously in 1657, whose narrator straps bottles of dew to himself, gets no further than New France, and arrives on the Moon at the third attempt only because soldiers have fixed rockets to his machine. Arthur C. Clarke credited that book with the first description of rocket-powered flight in print. Any Frenchman inventing a moonship in 1804 had a hundred and fifty years of that behind him. Our correspondent’s draughtsman used none of it.
What he drew instead is a shell. The ogival nose, the riveted belt courses, the proportion of length to diameter, the legs folded for stowage: these are the marks of an object meant to be fired. The boiler is ornament: there is nothing outside the atmosphere for steam to push against, and no nozzle drawn for it to push through. Which is to say that the plate belongs to a book nobody had written. Jules Verne published the Columbiad in 1865, and specified in the text a gun nine hundred feet long with a bore of one hundred and eight inches, four hundred thousand pounds of gun-cotton behind a projectile of twenty thousand, and an initial velocity of twelve thousand yards in the second. The Bureau will come shortly to what that last figure does to the people inside. For now it records only that the drawing is sixty-one years early.
The Question of the Cheese
The funding is the part the Executor tells with the most relish. There was, he writes, a surplus of cheese in the imperial stores, hoarded on the Emperor’s private conviction that a body so nearly resembling the Moon must prove useful in reaching it. It was quietly sold, and the proceeds went to the yard. The Bureau will take that seriously, because Napoleon’s spending on science is among the best-documented things about him, and the pattern of it is the opposite of secret.
He was elected to the Institut National in December 1797, at twenty-eight, with no scientific work to his name, into the chair vacated when Carnot was expelled after Fructidor; Monge and Berthollet arranged it over a dinner, and when he offered the company a compass construction picked up in Italy, Laplace replied that they had expected everything of the general except lessons in geometry. He then named one hundred and sixty-seven savants to a commission for Egypt, all but sixteen of whom sailed — twenty-one mathematicians, three astronomers, seventeen civil engineers among them — and founded the Institut d’Égypte at Cairo on 22 August 1798, which first sat two days later with forty-eight members in four sections, Monge presiding and Bonaparte, who had convened it, as his deputy. In 1801 he took the presidency of the Academy of Sciences himself and made Delambre its permanent secretary for the mathematical sciences, for life. When he wanted a thing invented he said so in public and paid for it in public: the army’s twelve thousand francs for preserving food went to Nicolas Appert in 1810, on the express condition that he publish the method.
This is not a man who buried an expedition in an attic. He put his survey of a conquered country into thirty-seven volumes, and his own name second on the letterhead of his own academy. And nowhere in those volumes, nor in the Connaissance des temps, nor in the registers of the Bureau des Longitudes, nor in the night books of the Paris Observatory — whose directors across these exact years were Lalande, then Méchain, then Delambre — is there an entry for cheese.
The Arithmetic of Getting Off the Ground
The Bureau now does the sum, and proposes to do it in the order an artillery officer would, the Emperor having been one. Charge, then speed, then what the speed costs the man inside.
Powder first. Take the twelve-pounder that carries the name Napoleon — named, as it happens, for the nephew and not the Emperor, adopted in 1857, and the commonest smoothbore of the American Civil War. It throws solid shot at 1,485 feet in the second, which is 453 metres, on two and a half pounds of powder: half a century of metallurgy later than the date on the diary, and a better gun than anything in the Emperor’s parks. Set 453 against 11,186 and it is short by a factor of twenty-five. Because energy goes as the square of speed, the shortfall in what must be crammed behind every pound of shot is not twenty-five-fold but better than six-hundred-fold. The Gribeauval twelve-pounder the Emperor actually commanded was effective to nine hundred metres and could not be persuaded past eighteen hundred.
Nor is this a question of a larger charge. A gun’s muzzle velocity is capped near the speed of sound in its own propellant gas, which is exactly why hypervelocity laboratories abandoned powder and drive their projectiles with hydrogen and helium — sound runs 3.8 and 3 times faster in those than in air — and even those stop somewhere around 7 to 8.5 kilometres in the second. A black-powder musket, which is what the Emperor’s infantry actually carried, makes between 120 and 370 metres in the second; the best modern rifle passes 1,200, and a tank gun throwing a dart 1,700. And the sixteen-inch naval barrels Gerald Bull stretched to a hundred and twenty feet — the one standing on Barbados was the largest operational artillery piece in the world at the time — put their record shot 180 kilometres up from Yuma in 1966, well past the hundred-kilometre line, and did not put it into orbit, and nothing has been put into orbit by a gun since.
What Twenty-Two Thousand Gravities Do
Verne, to his credit, published his figures, so the Bureau has done the division on them. Twelve thousand yards in the second is 10,973 metres. Reaching that inside nine hundred feet of barrel — 274 metres — requires an acceleration of some 219,000 metres in the second squared, which is a shade over twenty-two thousand times gravity. Seventy kilograms of Emperor would have borne down on the floor of that capsule with something over fifteen hundred tonnes.
Set that against what a body will take. A man loses consciousness at about five; nine is a pilot in a g-suit doing the straining drill; twenty is survivable for rather less than ten seconds. The highest peak anybody has deliberately ridden and walked away from is 46.2, on a rocket sled in 1954, by a volunteer who was strapped to it on purpose and who lived another forty-five years. Twenty-two thousand is not a hard voyage. It is not a voyage at all: it is the instantaneous conversion of a crew into a stain on a bulkhead, and it happens before the projectile has cleared the muzzle.
This, incidentally, is the objection the record itself makes to Verne. A gun cannot both reach escape velocity and keep the acceleration inside what a passenger will bear, unless the barrel is made very much longer than nine hundred feet — which is to say, unless it stops being a gun.
Invited to comment, the Executor replied that the Emperor was a soldier and accustomed to hardship.
A Calendar the File Cannot Keep
The Bureau’s practice with a document of uncertain date is to ask not what it claims but what it borrows, and from when. Some of this file could have been assembled in 1804 out of things a Frenchman had to hand. Most of it could not.
What was to hand was balloons, and France had them first and had them properly. The Montgolfiers sent an envelope up over Annonay on 4 June 1783 and a sheep, a duck and a cockerel over Versailles that September, and on 21 November Pilâtre de Rozier and the Marquis d’Arlandes crossed nine kilometres of Paris at about nine hundred metres. The Committee of Public Safety raised an aerostatic corps of twenty-six men in April 1794, and at Fleurus that June L’Entreprenant hung over the field for nine hours while its observers dropped written notes to the ground. That corps sailed for Egypt with the expedition. Its equipment went down with the fleet at the Nile, and the aeronauts spent the campaign giving demonstration ascents as entertainment. The Directory disbanded them on 15 January 1799, five years before the date on the diary.
And here is the ceiling of the whole enterprise. In that same year of 1804, Gay-Lussac went up alone from Paris with a barometer, a thermometer and empty flasks, reached 7,016 metres, and came down. It was the greatest height any human being had reached, and he stopped because the air did. The Moon is 384,399 kilometres off. He had covered one part in fifty-five thousand of the distance, and he had used up the atmosphere doing it.
What the File Borrows, and When It Was Available
The Executor dates his diary to 1804. The Bureau sets the sources of its contents against that year.
Cyrano de Bergerac’s narrator reaches the Moon in a machine to which soldiers have fixed rockets — the first rocket flight in print, and the one French precedent the file ignores.
Montgolfier envelopes fly at Annonay in June; Pilâtre de Rozier and d’Arlandes cross nine kilometres of Paris in November.
The Aerostatic Corps is raised in April. L’Entreprenant observes Fleurus from the air for nine hours in June.
The Directory disbands the balloon corps on 15 January. France has no military aeronauts thereafter.
Albert Mathieu proposes a Channel tunnel ventilated by iron chimneys standing out of the sea. Bonaparte, presumed to have seen the plans in Paris, raises the scheme with Charles James Fox.
London print shops sell the invasion arriving by sea, by tunnel and by balloon at once. The aerial fleet is an English idea about a Frenchman.
The date on the Executor’s diary. In the same year Gay-Lussac reaches 7,016 metres and comes down.
Congreve’s rockets — two thousand of them from twenty-four cutters in half an hour off Boulogne, to limited effect — are reaching three thousand yards, and scattering over hundreds.
The New York Sun runs six articles giving the Moon bison, single-horned goats and a race of winged men. It concedes the fabrication on 16 September and never retracts it.
Verne publishes the Columbiad: nine hundred feet of barrel, a bore of one hundred and eight inches, twelve thousand yards in the second.
A sixteen-inch gun at Yuma puts a shot 180 kilometres up, past the hundred-kilometre line, and no further. Nothing has reached orbit from a gun, then or since.
The Landing, the Craters and the Omelette
The landing narrative is mercifully short, and the Bureau takes it in the order the Executor gives it. The Emperor came down on a plain of craters. He planted the tricolour and said La lune est à moi. He then attempted to reduce the craters and found them resistant to his advances. He came home with a quantity of grey rock which he judged would make the finest omelette in France.
The flag first, because the plate settles it. The cloth in that picture is flying: the fly stands clear of the staff with a full curve of wind in it. There is no air on the Moon to fly it in. The entire exosphere weighs under ten tonnes; the pressure at the surface is about three thousand-millionths of a millionth of an atmosphere; and where a cubic centimetre of air at sea level holds something like ten to the nineteenth molecules, the same volume up there holds fewer than a million. There is nothing there to push cloth, and a full curve of wind is the one thing that plain cannot produce.
The craters next, and the Bureau raises this as a military objection rather than a scientific one. A crater is a hole. It has no garrison, no walls to breach, no line of supply to cut and nothing whatever to resist with. The best field commander of his century did not write that sentence, because it is not a sentence a soldier can think.
The greatcoat, briefly. He is painted bare-faced in wool over a uniform coat. Surface temperature on that plain runs from 120 °C in the sun to 171 below in the shade, with no air to carry heat from the one to the other, so that the lit side and the shaded side of the same man stand in different climates.
The omelette last. One cannot be made without breaking eggs, and there is nothing on that plain to break.
What the Bureau Is Able to Certify
The Bureau is able to certify that Napoleon Bonaparte sat in the Institut National, shipped a hundred and fifty-one savants to Egypt and founded an academy for them in Cairo; that in the year of the diary a Frenchman carried a thermometer seven kilometres into the air over Paris and came back down; and that the British public of 1803 genuinely expected him to arrive by balloon, by tunnel and by sea at once. It is not able to certify that anything of his ever went higher than Gay-Lussac did.
It holds one objection back for the end. The Moon in this file is empty, and empty is the modern answer. The Moon the reading public carried about with it in 1804 was furnished and inhabited, and stayed so long enough for the New York Sun to stock it in 1835 with bison, single-horned goats and a race of winged men, and for a great many readers to settle the account. A man forging in 1804 would have put something on that plain: a city, a prince, an embassy, a war worth the Emperor’s attention. This one knew there was nothing there, and knowing there is nothing there is a conclusion that took a century and a half of instruments to reach.
We wrote a last time to the rue du Cherche-Midi and asked for one thing that could be measured — a single leaf of the diary, released for examination of the paper and the iron in the ink. The reply came by return. The diary cannot leave the attic, because it is the attic that authenticates the diary. The Executor adds that the Emperor would have taken the point at once, and that we would take it ourselves if we had ever been trusted with anything.
The file remains open.
