1.  Automobile:

Henry Ford, son of an Irish immigrant, transformed the world with his low price automobile which created modern life, suburbs, highways, mobility etc, forever.

2. Submarine:

John Philip Holland, from Clare, invented the submarine and it was commissioned in 1900 by the US Navy.

3. Tractor:

Harry Ferguson, from Northern Ireland, a bicycle repair man with a genius for mechanical inventions, invented the modern tractor as well as the first four wheel drive Formula One racing car.

4. Tank:

When Winston Churchill, in 1915, issued an all points bulletin for the invention of a machine capable of withstanding rifle fire, flattening barbed wire fences, and rolling over no man’s land Irishman Walter Gordon Wilson obliged by inventing the modern tank.

5. Color photography:

John Joly, from County Down, was the first to invent the color photograph back in 1894, although it did not gain widespread acceptance until many years later.

6. Monorail:

Louis Brennan, from Mayo, was the inventor of the monorail. He did much of the work on a monorail locomotive which was kept upright by a gyrostat. In 1903 he patented a system that he designed for military use; he successfully demonstrated the system, on November 10, 1909, in Gillingham, England.

7. Nickel Zinc battery:

The battery was developed by an Irish chemist, Dr. James J. Drumm (1897–1974) and installed in four two-car railway sets, between 1932 and 1948, for use on the Dublin-Bray railway line. Today it is used to power cell phones.

8. Splitting the atom:

Ernest Thomas Sinton Walton, a physicist from Dungarvan, Co Waterford, won the Nobel Prize for his work with John Cockcroft. In the late 1920s/early 1930s, the two conducted "atom-smashing" experiments at Cambridge University. Walton became the first person to artificially split the atom..
9. Guinness:

Enough said.

10. Milk chocolate:

In the 18th century Sir Hans Sloane, from County Down, encountered cocoa while he was in Jamaica, where the locals drank it mixed with water, and he is reported to have found it nauseating. However, he devised a means of mixing it with milk to make it more pleasant. When he returned to England, he brought his chocolate recipe back with him. By the 19th century, Cadburys was selling tins of Sloane's drinking chocolate. 

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