1761: Mikhail Lomonosov writes an article where he conludes that Venus has an atmosphere. Two days earlier, on June 6, a rare astronomical event took place, Venus transit across the disk of the Sun. In 1761, hundreds of astronomers observed this event, trying to calculate the distance from Earth to Venus. Russian Academy of Sciences sent an expedition to Irkutsk, but Lomonosov stayed in St.Petersburg. He used a small 135 mm long telescope and a smoked glass. Using these imperfect tools, he managed to note that Venus was at this moment surrounded by a light rim. He deduced that this rim may be explained by the refraction of the light in the atmosphere of Venus. He also noted some vagueness of the edge of the Sun disk when Venus touched it. This effect still remains unexplained. On June 7, he begins writing an article using his own observations and the data obtained by other astronomers, A.Krasilnikov and N.Kurganov. The article was published in Russian and German languages, but passed unnoticed by other astronomers. Only in 1790s William Herschel re-discovered the Venus atmosphere. In the XX century, Lomonosov's priority was restored. Lomonosov's sketch and excerpts from his article (in Russian) may be found on the web-site of the Samara Children's and Youth Arts and Sciences Centre. Transit of Venus is a rare event and the last time it took place in 2004, when I tried to observe it using a floppy disk as a filter. I am pretty sure that that tiny black spot was Venus :). Anyway, in 2014 I will have a chance to try again. After that, the next transit will happen only in 2117.
1827: (May 27 old style) Alexander Pushkin wrote to his friend Peter Vyazemsky the words which many Russians might repeat:
Of course, I scorn my fatherland from head to toes — but I am vexed if a foreigner shares this feeling with me. You, who is not on the leash, how can you stay in Russia? If the tsar gives me freedom, I won't stay here for more than one month. We live in sad years, but when I imagine London, railroads, steamships, English magazines or Paris theatres and brothels, my god-forsaken Mikhailovskoye brings upon me ennui and madness. In the 4th chapter of Eugene Onegin I portrayed my life; one day you will read it and ask with a sweet smile: where is my poet now? he was so gifted, and the reply will be: he's gone to Paris and will never be back, what a smart boy!
(Original Russian text is here.)
1948: The first Soviet industrial nuclear reactor is launched in a small town in Urals mountains, known as Base-10, Chelyabinsk-40 or Chelyabinsk-65. Now, this town is named Ozyorsk. The town was built for this exactly purpose. The works were started on 9 November 1945. This town became later famous due to the new chemical factory, called Mayak, one of the largest Russian plants working with radioactive materials. In 1957, one of the largest radioactive leaks in history happened on this factory.