1.

It occurred to me that if I could invent a machine—a gun—which could by its rapidity of fire, enable one man to do as much battle duty as a hundred, that it would, to a large extent supersede the necessity of large armies, and consequently, exposure to battle and disease [would] be greatly diminished.

Richard Gatling (1861)

2.

In 1923, Hermann Oberth published The Rocket to Planetary Spaces, later expanded as Ways to Space Travel. This showed that it was possible to build machines that could leave Earth’s atmosphere and reach orbit. He described the general principles of multiple-stage liquid-fueled rockets, solar sails, and even ion drives. He proposed sending humans into space, building space stations and satellites, and travelling to other planets.

The idea of space travel became popular in Germany. Swept up by these ideas, in 1927, Johannes Winkler, Max Valier, and Willy Ley formed the Verein für Raumschiffahrt (VfR) (Society for Space Travel) in Breslau (now Wrocław, Poland). This group rapidly grew to several hundred members. Several participated as advisors of Fritz Lang’s The Woman in the Moon, and the VfR even began publishing their own journal.

In 1930, the VfR was granted permission to use an abandoned ammunition dump outside Berlin as a test site and began experimenting with real rockets. Over the next few years, they developed a series of increasingly powerful rockets, first the Mirak line (which flew to a height of 18.3 m), then the Repulsor (>1 km). These people dreamed of space travel, and were building rockets themselves, funded by membership dues and a few donations. You can just do things.

However, with the great depression and loss of public interest in rocketry, the VfR faced declining membership and financial problems. In 1932, they approached the army and arranged a demonstration launch. Though it failed, the army nevertheless offered a contract. After a tumultuous internal debate, the VfR rejected the contract. Nevertheless, the army hired away several of the most talented members, starting with a 19-year-old named Wernher von Braun.

Following Hitler’s rise to power in January 1933, the army made an offer to absorb the entire VfR operation. They would work at modern facilities with ample funding, but under full military control, with all work classified and an explicit focus on weapons rather than space travel. The VfR’s leader, Rudolf Nebel, refused the offer, and the VfR continued to decline. Launches ceased. In 1934, the Gestapo finally shut the VfR down, and civilian research on rockets was restricted. Many VfR members followed von Braun to work for the military.

Of the founding members, Max Valier was killed in an accident in May 1930. Johannes Winkler joined the SS and spent the war working on liquid-fuel engines for military aircraft. Willy Ley was horrified by the Nazi regime and in 1935 forged some documents and fled to the United States, where he was a popular science author, seemingly the only surviving thread of the spirit of Oberth’s 1923 book. By 1944, V-2 rockets were falling on London and Antwerp.

3.

North Americans think the Wright Brothers invented the airplane. Much of the world believes that credit belongs to Alberto Santos-Dumont, a Brazilian inventor working in Paris.

Though Santos-Dumont is often presented as an idealistic pacifist, this is hagiography. In his 1904 book on airships, he suggests warfare as the primary practical use, discussing applications in reconnaissance, destroying submarines, attacking ships, troop supply, and siege operations. As World War I began, he enlisted in the French army (as a chauffeur), but seeing planes used for increasing violence disturbed him. His health declined and he returned to Brazil.

His views on military uses of planes seemed to shift. Though planes contributed to the carnage in WWI, he hoped that they might advance peace by keeping European violence from reaching the American continents. Speaking at a conference in the US in late 1915 or early 1916, he suggested:

Here in the new world we should all be friends. We should be able, in case of trouble, to intimidate any European power contemplating war against any one of us, not by guns, of which we have so few, but by the strength of our union. […] Only a fleet of great aeroplanes, flying 200 kilometers an hour, could patrol these long coasts.

Following the war, he appealed to the League of Nations to ban the use of planes as weapons and even offered a prize of 10,000 francs for whoever wrote the best argument to that effect. When the Brazilian revolution broke out in 1932, he was horrified to see planes used in fighting near his home. He asked a friend:

Why did I make this invention which, instead of contributing to the love between men, turns into a cursed weapon of war?

He died shortly thereafter, perhaps by suicide. A hundred years later, banning the use of planes in war is inconceivable.

4.

Humanity had few explosives other than gunpowder until 1847 when Ascanio Sobrero created nitroglycerin by combining nitric and sulfuric acid with a fat extract called glycerin. Sobrero found it too volatile for use as an explosive and turned to medical uses. After a self-experiment, he reported that ingesting nitroglycerin led to “a most violent, pulsating headache accompanied by great weakness of the limbs”. (He also killed his dog.) Eventually this led to the use of nitroglycerin for heart disease.

Many tried and failed to reliably ignite nitroglycerin. In 1863, Alfred Nobel finally succeeded by placing a tube of gunpowder with a traditional fuse inside the nitroglycerin. He put on a series of demonstrations blowing up enormous rocks. Certain that these explosives would transform mining and tunneling, he took out patents and started filling orders.

The substance remained lethally volatile. There were numerous fatal accidents around the world. In 1867, Nobel discovered that combining nitroglycerin with diatomaceous earth produced a product that was slightly less powerful but vastly safer. His factories of “dynamite” (no relation) were soon producing thousands of tons a year. Nobel sent chemists to California where they started manufacturing dynamite in a plant in what is today Golden Gate Park. By 1874, he had founded dynamite companies in more than ten countries and he was enormously rich.

In 1876, Nobel met Bertha Kinsky, who would become Bertha von Suttner, a celebrated peace activist. (And winner of the 1905 Nobel Peace Prize). At their first meeting, she expressed concern about dynamite’s military potential. Nobel shocked her. No, he said, the problem was that dynamite was too weak. Instead, he wished to produce “a substance or invent a machine of such frightful efficacy for wholesale destruction that wars should thereby become altogether impossible”.

It’s easy to dismiss this as self-serving. But dynamite was used overwhelmingly for construction and mining. Nobel did not grow rich by selling weapons. He was disturbed by dynamite’s use in Chicago’s 1886 Haymarket bombing. After being repeatedly betrayed and swindled, he seemed to regard the world of money with a kind of disgust. At heart, he seemed to be more inventor than businessman.

Still, the common story that Nobel was a closet pacifist is also hagiography. He showed little concern when both sides used dynamite in the 1870-1871 Franco-Prussian war. In his later years, he worked on developing munitions and co-invented cordite, remarking that they were “rather fiendish” but “so interesting as purely theoretical problems”.

Simultaneously, he grew interested in peace. He repeatedly suggested that Europe try a sort of one-year cooling off period. He even hired a retired Turkish diplomat as a kind of peace advisor. Eventually, he concluded that peace required an international agreement to act against any aggressor.

When Bertha’s 1889 book Lay Down Arms became a rallying cry, Nobel called it a masterpiece. But Nobel was skeptical. He made only small donations to her organization and refused to be listed as a sponsor of a pacifist congress. Instead, he continued to believe that peace would come through technological means, namely more powerful weapons. If explosives failed to achieve this, he told a friend, a solution could be found elsewhere:

A mere increase in the deadliness of armaments would not bring peace. The difficulty is that the action of explosives is too limited; to overcome this deficiency war must be made as deadly for all the civilians back home as for the troops on the front lines. […] War will instantly stop if the weapon is bacteriology.

5.

I’m a soldier who was tested by fate in 1941, in the very first months of that war that was so frightening and fateful for our people. […] On the battlefield, my comrades in arms and I were unable to defend ourselves. There was only one of the legendary Mosin rifles for three soldiers.

[…]

After the war, I worked long and very hard, day and night, labored at the lathe until I created a model with better characteristics. […] But I cannot bear my spiritual agony and the question that repeats itself over and over: If my automatic deprived people of life, am I, Mikhail Kalashnikov, ninety-three years of age, son of a peasant woman, a Christian and of Orthodox faith, guilty of the deaths of people, even if of enemies?

For twenty years already, we have been living in a different country. […] But evil is not subsiding. Good and evil live side by side, they conflict, and, what is most frightening, they make peace with each other in people’s hearts.

Mikhail Kalashnikov (2012)

6.

In 1937 Leo Szilárd fled Nazi Germany, eventually ending up in New York where—with no formal position—he did experiments demonstrating that uranium could likely sustain a chain reaction of neutron emissions. He immediately realized that this meant it might be possible to create nuclear weapons. Horrified by what Hitler might do with such weapons, he enlisted Einstein to write the 1939 Einstein–Szilárd letter, which led to the creation of the Manhattan project. Szilárd himself worked for the project at the Metallurgical Laboratory at the University of Chicago.

On June 11, 1945, as the bomb approached completion, Szilárd co-signed the Franck report:

Nuclear bombs cannot possibly remain a “secret weapon” at the exclusive disposal of this country, for more than a few years. The scientific facts on which their construction is based are well known to scientists of other countries. Unless an effective international control of nuclear explosives is instituted, a race of nuclear armaments is certain to ensue.

[…]

We believe that these considerations make the use of nuclear bombs for an early, unannounced attack against Japan inadvisable. If the United States would be the first to release this new means of indiscriminate destruction upon mankind, she would sacrifice public support throughout the world, precipitate the race of armaments, and prejudice the possibility of reaching an international agreement on the future control of such weapons.

On July 16, 1945, the Trinity test achieved the first successful detonation of a nuclear weapon. The next day, he circulated the Szilárd petition:

We, the undersigned scientists, have been working in the field of atomic power. Until recently we have had to fear that the United States might be attacked by atomic bombs during this war and that her only defense might lie in a counterattack by the same means. Today, with the defeat of Germany, this danger is averted and we feel impelled to say what follows:

The war has to be brought speedily to a successful conclusion and attacks by atomic bombs may very well be an effective method of warfare. We feel, however, that such attacks on Japan could not be justified, at least not unless the terms which will be imposed after the war on Japan were made public in detail and Japan were given an opportunity to surrender.

[…]

The development of atomic power will provide the nations with new means of destruction. The atomic bombs at our disposal represent only the first step in this direction, and there is almost no limit to the destructive power which will become available in the course of their future development. Thus a nation which sets the precedent of using these newly liberated forces of nature for purposes of destruction may have to bear the responsibility of opening the door to an era of devastation on an unimaginable scale.

[…]

In view of the foregoing, we, the undersigned, respectfully petition: first, that you exercise your power as Commander-in-Chief, to rule that the United States shall not resort to the use of atomic bombs in this war unless the terms which will be imposed upon Japan have been made public in detail and Japan knowing these terms has refused to surrender; second, that in such an event the question whether or not to use atomic bombs be decided by you in the light of the consideration presented in this petition as well as all the other moral responsibilities which are involved.

The Truman administration did not adopt this recommendation.