The Diamond Necklace Affair or How to Destroy a French Queen
Jeanne is a con artist who orders a diamond necklace and sends the bill to the Queen. The Queen denies ever ordering the necklace, and accuses Cardinal de Rohan of a plot to discredit her. (She and the Cardinal often fought at court.) How did it all happen? Jeanne claimed to be a descendant of one of the kings of France. She had been sleeping with Cardinal de Rohan and convinced him that the Queen wished him to purchase a diamond necklace on her behalf. When the bill came, the Queen denied ever purchasing the necklace. The Cardinal insisted that she did, pointing out that the Queen was standing before him when she did. (It was an imposter than Jeanne arranged.) In the end, the Queen is exonerated but so is the Cardinal. In the public's eye, she looks like a self-involved knucklehead. More importantly, any future rumor, no matter how fantastic, is now believed. Thus when the people are starving from lack of bread, they believe the rumor that she said, "Let them eat cake!" Could it ever be worse? Why yes. It could be and will be.  
Steam-Powered Locomotion and the "Puffing Devil"
It is a "steam carriage" or "road locomotive." No rails involved. (Don't be silly. Rail cars are pulled by horses!) William Murdoch is the man who helped James Watt improve the Boulton-and-Watt steam engine. He rearranged the gears and increased the efficiency. Murdoch's basic steam engine design is still used in the modern day for some applications, but he is best known for his experiments with the first locomotive and for gas lighting. His first locomotive is just a model about 2 feet tall, but that oscillating steam cylinder that goes "chug-a-chug" with an arm attached to a wheel is his invention. When you see it, you know. That is part of a locomotive.   
Other Important Events
- Benjamin Franklin invents bifocal glasses. It seems that he invented them independently from others who also invented bifocals. The term "bifolocal" won't come into use until much later. 
- The 'puddling process' for making wrought iron is patented. The process needs improvement but they are on their way! 
This Year in Wikipedia
Year 1784, Wikipedia.
- Beckman, Jonathan. How to Ruin a Queen: Marie Antoinette and the Diamond Necklace Affair. Da Capo Press.
- Affair of the Diamond Necklace - Wikipedia (2016). Retrieved on 11 May 2016. “Despite the findings to the contrary, many people in France persisted in the belief that the Queen had used the La Mottes as an instrument to satisfy her hatred of the Cardinal de Rohan. Various circumstances fortified this belief. There was the Queen's disappointment at Rohan's acquittal, and the fact that the Cardinal was afterwards deprived by the King of his charges and exiled to the Abbey of la Chaise-Dieu. In addition, the people assumed that the Parlement de Paris's acquittal of Rohan implied that Marie Antoinette was somehow in the wrong. All of these factors led to a huge decline in the Queen's popularity and encouraged an image of her among the masses as a manipulative spendthrift, interested more in vanity than in the welfare of France and the French.”
- Jeanne de Valois-Saint-Rémy - Wikipedia (2016). Retrieved on 11 May 2016. “The public sympathized with her. She was condemned to prison for life in the Salpêtrière, but soon escaped disguised as a boy and made her way to London where, in 1789, she published her memoirs entitled Memoires Justificatifs de La Comtesse de Valois de La Motte, which attempted to justify her actions while casting blame upon her chief victim, Marie Antoinette.”
- The Lunar Men who shaped the future: Murdock Locomotive. Birmingham Stories (2014). “This miniature locomotive was the very first self-propelled vehicle in England. Steam moved a tiny 20mm piston inside a small cylinder, which gave power for the vehicle to travel. It was designed in about 1784 by William Murdock, a friend and employee of Matthew Boulton and James Watt, members of the famous Lunar Society of Birmingham.”
- William Murdoch - Wikipedia (2016). Retrieved on 2014. “Murdoch's working model was a three-wheeled vehicle about a foot in height with the engine and boiler placed between the two larger back wheels with a spirit lamp underneath to heat the water and a tiller at the front turning the smaller front wheel. The mechanics of the model locomotive incorporated a number of innovations, such as a boiler safety valve, having the cylinder partly immersed in the boiler and using a new valve system on the lines of the D-slide valve.”
- James Watt - Wikipedia, 2014 [last update]
- Steam locomotive - Wikipedia (2016). Retrieved on 11 May 2016. “The first full-scale working railway steam locomotive was also built by Richard Trevithick, called the 'Puffing Devil,' in the United Kingdom and, on 21 February 1804, the world's first railway journey took place as Trevithick's unnamed steam locomotive hauled a train along the tramway from the Pen-y-darren ironworks, near Merthyr Tydfil, to Abercynon in South Wales”
- Trevithick Trail: Merthyr Tydfil to Abercynon - Sustrans. sustrans.org.uk (2016). Retrieved on 11 May 2016. “On this tramway the Penydarren locomotive entered World history by becoming the first ever steam-powered railway locomotive to pull a load on rails. A 500 guinea bet was made by local iron masters that it couldn't haul 10 tonnes of iron. The stakes were high, but on the 21st of January 1804, after 4 hours and a broken track, Richard Trevithick's engine completed the 9 miles from Penydarren to Abercynon!”
- Bifocals - Wikipedia (2016). Retrieved on 11 May 2016. “Benjamin Franklin is generally credited with the invention of bifocals. Historians have produced some evidence to suggest that others may have come before him in the invention; however, a correspondence between George Whatley and John Fenno, editor of The Gazette of the United States, suggested that Franklin had indeed invented bifocals, and perhaps 50 years earlier than had been originally thought. Since many inventions are developed independently by more than one person, it is possible that the invention of bifocals may have been such a case. Nonetheless, Benjamin Franklin was among the first to wear bifocal lenses, and Franklin's letters of correspondence suggest that he invented them independently, regardless of whether he was the first to invent them.”
- Puddling (metallurgy) - Wikipedia (2016). Retrieved on 11 May 2016. “Cort's process consisted of stirring molten pig iron in a reverberatory furnace in an oxidising atmosphere, thus decarburising it. When the iron 'came to nature', that is, to a pasty consistency, it was gathered into a puddled ball, shingled, and rolled (as described below). This application of the rolling mill was also Cort's invention.”
- Grun, Bernard. The Timetables of History: A Horizontal Linkage of People and Events. Simon and Schuster, 364-365.
- Argand lamp - Wikipedia (2016). Retrieved on 11 May 2016. “The Argand lamp was introduced to Thomas Jefferson in Paris in 1784 and according to him gave off 'a light equal to six or eight candles.'”