a German Jewish and Russian engineer and physicist born in Potsdam. Jacobi worked mainly in Russia. He furthered progress in galvanoplastics, electric motors, and wire telegraphy. While studying the transfer of power from a battery to an electric motor, he deduced the maximum power theorem. Jacobi tested motors output by determining the amount of zinc consum...

a German Jewish and Russian engineer and physicist born in Potsdam. Jacobi worked mainly in Russia. He furthered progress in galvanoplastics, electric motors, and wire telegraphy. While studying the transfer of power from a battery to an electric motor, he deduced the maximum power theorem. Jacobi tested motors output by determining the amount of zinc consumed by the battery. With financial assistance of Czar Nicholas, Jacobi constructed in 1839 a 28-foot electric motor boat powered by battery cells. The boat carried 14 passengers on Neva river against the current. The boat fared at the speed of three miles for hour.

a French weaver and merchant. He played an important role in the development of the earliest programmable loom (the "Jacquard loom"), which in turn played an important role in the development of other programmable machines. His mother died in 1762, and when his father died in 1772, Joseph inherited his father’s house, looms and workshop as well as a vineya...

a French weaver and merchant. He played an important role in the development of the earliest programmable loom (the "Jacquard loom"), which in turn played an important role in the development of other programmable machines. His mother died in 1762, and when his father died in 1772, Joseph inherited his father’s house, looms and workshop as well as a vineyard and quarry in Couzon-au-Mont d’Or. Joseph then dabbled in real estate. In 1778, he listed his occupations as master weaver and silk merchant.

a Dutch spectacle-maker from Middelburg associated with the invention of the first optical telescope. Janssen is sometimes also credited for inventing the first truly compound microscope. However, the origin of the microscope, just like the origin of the telescope, is a matter of debate. Over the years there have been claims Zacharias Janssen invented the te...

a Dutch spectacle-maker from Middelburg associated with the invention of the first optical telescope. Janssen is sometimes also credited for inventing the first truly compound microscope. However, the origin of the microscope, just like the origin of the telescope, is a matter of debate. Over the years there have been claims Zacharias Janssen invented the telescope and/or the microscope in Middelburg between 1590 and 1618.

an American physician and politician. He was brother of John Jay, one of the Founding Fathers of the United States. While initially a supporter of American independence, he later changed his views becoming a Loyalist and went into exile in London after the Treaty of...

an American physician and politician. He was brother of John Jay, one of the Founding Fathers of the United States. While initially a supporter of American independence, he later changed his views becoming a Loyalist and went into exile in London after the Treaty of Paris recognised independence. Invisible ink was used occasionally after Sir James Jay invented two special fluids, and sent a supply to his brother John Jay in New York. Sir James would use the ink at the bottom of brief, friendly letters to his brother and even send the letters unsealed, so that British authorities might inspect the contents.

a Hungarian inventor, engineer, physicist, and Benedictine priest. He was also a member of the Hungarian Academy of Sciences, and author of several books. He is considered by Hungarians and Slovaks to be the unsung father of the dynamo and electric motor. Jedlik's best known invention is the principle of dynamo self-excitation. In 1827, Jedlik started experi...

a Hungarian inventor, engineer, physicist, and Benedictine priest. He was also a member of the Hungarian Academy of Sciences, and author of several books. He is considered by Hungarians and Slovaks to be the unsung father of the dynamo and electric motor. Jedlik's best known invention is the principle of dynamo self-excitation. In 1827, Jedlik started experimenting with electromagnetic rotating devices which he called electromagnetic self-rotors. In the prototype of the single-pole electric starter, both the stationary and the revolving parts were electromagnetic. In essence, the concept is that instead of permanent magnets, two opposed electromagnets induce the magnetic field around the rotor.

settled in Lynn, Massachusetts by 1643, arriving as a widower. On March 6, 1646, he was awarded the first patent in North America by the General Court of Massachusetts, for making scythes. This basic scythe design remained in use for over 300 years. In 1654 he built the first fire engine in North America, commissioned by the city of Boston. The site of the J...

settled in Lynn, Massachusetts by 1643, arriving as a widower. On March 6, 1646, he was awarded the first patent in North America by the General Court of Massachusetts, for making scythes. This basic scythe design remained in use for over 300 years. In 1654 he built the first fire engine in North America, commissioned by the city of Boston. The site of the Jenckes forge is at the Saugus Iron Works National Historic Site.

settled in Lynn, Massachusetts by 1643, arriving as a widower. On March 6, 1646, he was awarded the first patent in North America by the General Court of Massachusetts, for making scythes. This basic scythe design remained in use for over 300 years. In 1654 he built the first fire engine in North America, commissioned by the city of Boston. The site of the J...

settled in Lynn, Massachusetts by 1643, arriving as a widower. On March 6, 1646, he was awarded the first patent in North America by the General Court of Massachusetts, for making scythes. This basic scythe design remained in use for over 300 years. In 1654 he built the first fire engine in North America, commissioned by the city of Boston. The site of the Jenckes forge is at the Saugus Iron Works National Historic Site.

an African-American tradesman and abolitionist in New York City, New York. He operated and owned a tailoring and dry-cleaning business, and, on March 3,1821, he was granted patent 3306x for a dry scrub process as the first African American to be granted a patent. Jennings became active in working for his race and civil rights for the black community. In 1831...

an African-American tradesman and abolitionist in New York City, New York. He operated and owned a tailoring and dry-cleaning business, and, on March 3,1821, he was granted patent 3306x for a dry scrub process as the first African American to be granted a patent. Jennings became active in working for his race and civil rights for the black community. In 1831, he was selected as assistant secretary to the First Annual Convention of the People of Color in Philadelphia, Pennsylvania, which met in June 1831.

a coachmaker of Long Acre, London, England. He was a pioneer bicycle-maker. Johnson created an improved version of the German Karl Drais's Draisine, the archetypal bicycle. Johnson's ‘pedestrian curricle’ was patented in London in December 1818, becoming Britain's first bicycle. It featured an elegantly curved wooden frame, allowing the use of larger woo...

a coachmaker of Long Acre, London, England. He was a pioneer bicycle-maker. Johnson created an improved version of the German Karl Drais's Draisine, the archetypal bicycle. Johnson's ‘pedestrian curricle’ was patented in London in December 1818, becoming Britain's first bicycle. It featured an elegantly curved wooden frame, allowing the use of larger wooden wheels. Several parts were made of metal, which allowed the vehicle to be lighter than the continental version. Although Johnson referred to his machine as a ‘pedestrian curricle’, it was formally referred to as a ‘velocipede’, and popularly as a ‘Hobby-horse’, ‘Dandy-horse’, ‘Pedestrian's accelerator’, ‘Swift walker’ and by a variety of other names.

a German physicist and mathematician. e studied science in Heidelberg, Vienna and Berlin. After his studies, he was appointed professor of mathematics in Heidelberg in 1839 and in physics in 1846. He moved to Munich in 1854 where he took the position once held by Georg Simon Ohm. In 1854 he was knighted (and henceforth referred to as von Jolly). Jolly was fi...

a German physicist and mathematician. e studied science in Heidelberg, Vienna and Berlin. After his studies, he was appointed professor of mathematics in Heidelberg in 1839 and in physics in 1846. He moved to Munich in 1854 where he took the position once held by Georg Simon Ohm. In 1854 he was knighted (and henceforth referred to as von Jolly). Jolly was first and foremost an experimental physicist. He measured the acceleration due to gravity with precision weights and also worked on osmosis. He invented the Jolly balance, an instrument used for determining specific gravities.

claimed to be the first inventor of the steamboat. In 1773, Jouffroy d'Abbans met with the Perier (fr) brothers and studied in their workshop the Pompe à feu (Fire pump), which had been used as a motive force for the hydraulic machine developed by Chaillot, in order to apply to ship propulsion. In 1776, Jouffroy d'Abbans develop a 13-meter steamship, the Pa...

claimed to be the first inventor of the steamboat. In 1773, Jouffroy d'Abbans met with the Perier (fr) brothers and studied in their workshop the Pompe à feu (Fire pump), which had been used as a motive force for the hydraulic machine developed by Chaillot, in order to apply to ship propulsion. In 1776, Jouffroy d'Abbans develop a 13-meter steamship, the Palmipède, in which the engine moved oars equipped with rotating blades. The ship sailed on the Doubs in June and July 1776.