Alexander Bonner Latta was born on a farm near Chillicothe, Ross County, Ohio, the youngest of the six children of John and Rebecca (Bonner) Latta. When he was five years old his father was killed in an accident, leaving his widow penniless.
Latta attended a country school in Ohio until he was thirteen years old. He was forced to quit school to help support his mother and brothers.
Latta started to work in a cotton factory at the age of 10; subsequently he became an apprentice in a machine shop. Becoming an expert machinist, he settled in Cincinnati, Ohio, in the early forties, where he was foreman in the Harkness machine shop.
In 1845, under his directions, the first locomotive west of the Allegheny Mountains was built and had its trial trip from Cincinnati to Columbus and return, Latta acting as engineer. Subsequently, he designed and built a locomotive for the Boston & Maine Railroad. This machine had an extra pair of steam cylinders under the water tank, the steam being taken back and the exhaust being brought forward again through pipes fitted with ball joints. Between 1847 and the time of his death he secured a number of patents for improvements on steam engines, boilers, and locomotives, but by far his greatest inventive and manufacturing work was concerned with the development of the steam fire engine.
He completed his first engine in 1852 and sold it to Cincinnati, the first city in the United States to adopt the steamer as a part of its fire-department apparatus. Latta's engines were designed to be drawn by men or horses, but he perfected, also, a self-propelled machine. One of his patents for the latter type was granted May 22, 1855, Patent No. 12, 912.
It consisted of a three-wheeled chassis, the rear wheels being connected by rods to the same steam cylinders which furnished power to the water pumps. Upon arrival at the scene of a fire the engine was raised off the ground and supported by means of screws on the sides of the boiler, so that the rear wheels might be used as flywheels. The boiler in Latta's fire engines was constructed of two square chambers, one within the other, the space between being the steam and water space. The inner chamber, which was the firebox, was filled with a series of horizontal layers of tubes arranged diagonally over each other but forming one continuous coil. The water entered this coil at the lower end and passed upward into the annular area, where it was evaporated.
As his business developed, he formed a partnership with his brother, and by 1858 six out of the seven horse-drawn fire engines in Cincinnati had been made by them. They built all told about thirty, the last, in 1860, were ordered for the cities of Nashville and Memphis, Tennessee. These were not delivered until the Federal troops were in full control there. He retired from active business in 1862, but was engaged in inventive work at the time of his death. His death occurred in Ludlow, Kentucky.
Latta was known as a manufacturer of the first practical steam fire engine. It was successfully used as a routine part of a city's fire department equipment. He had built 30 steam locomotive engines by 1860. For his fire-engine improvements Latta was awarded a gold medal by the Ohio Mechanics Institute Fair in 1854.
Latta was married to Elizabeth Ann Pawson of Cincinnati in 1847. They had two children.
