The NPI is a 10-digit number consisting of 9 digits (with the first digit being a 1 or a 2) followed by a check digit. The check digit uses the Luhn algorithm, which is calculated like this: Double the value of alternate digits beginning with the rightmost digit.
Fossil fuels have been an essential source of energy since humans first discovered coal. From Neolithic times to the eighteenth century, humans made only minor improvements to coal and wood-burning technology. The steam engines of the 1700s were the first machines to use fossil fuels to power mechanical processes. By 1802, cities in Europe were using natural gas to operate street lamps and to create electricity. The first company in England to sell coal-gas for lighting was founded in 1806. In 1816, a coal-gas electric company was established in Baltimore Maryland. In 1823, inventor Samuel Brown created an internal combustion engine and demonstrated the potential of fossil fuels to power vehicles.
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years. Fossil fuels contain high percentages of carbon and include coal, petroleum and natural gas. Other more commonly used derivatives of fossil fuels include kerosene and propane.