28 Responses to The Real Origin of Viking Raids. 1  Well done! 2  Thank you for this article. 3  The shutting of the ancient trade routes to Rome and the East by the Holy Roman Empire was the principle reason that the Rus trade routes down the Volga were established. 4  Pingback: Daily Stuff 5-20-13 MjÃ¶lnir | Ancient Light's Daily Stuff.
By Anne Marie Helmenstine, Ph.D. Gunpowder or black powder is of great historical importance in chemistry. Although it can explode, its principal use is as a propellant. Gunpowder was invented by Chinese alchemists in the 9th century.Originally, it was made by mixing elemental sulfur, charcoal, and saltpeter (potassium nitrate).y Anne Marie Helmenstine, Ph.D. Gunpowder or black powder is of great historical importance in chemistry. Although it can explode, its principal use is as a propellant. Gunpowder was invented by Chinese alchemists in the 9th century.
Steamboat History. The steamboat represented an important phase in the development of shipping. Before the steamboat was invented, boats were powered by sail power. From the mid-19th to the mid-20th century, steamboats were the most important type of boats for transportation, trading and warfare.o start the process, water is fed to a boiler that heats it up until it produces steam. The steam is then fed into a piston cylinder. It pushes the piston up to the top of its stroke. When it reaches the top, a valve is opened in the side of the cylinder to vent out the steam.