de Prony brake dynamometers at a tractor contest in 1910. Schematic of a de Prony brake. The de Prony Brake is a simple device invented by Gaspard de Prony to measure the torque produced by an engine. The term  brake horsepower  is one measurement of power derived from this method of measuring torque. (Power is calculated by multiplying torque by rotational speed .).
Typically tree trunks are thought of as being in various shades of brown. They can have many different colours to them, however.Grey is a common colour in tree trunks, as is green when they're younger. Specific species of trees usually have specific bark colour at specific times of year so you should look up the trees you're interested in if you need more information.ypically tree trunks are thought of as being in various shades of brown. They can have many different colours to them, however.
Yellow fruit about the size of a tennis ball. Usually has a nipple on one end of the fruit. It is juicy with transparent flesh and a caramel like flavor. The tree is small to medium sized, 12 to 15 feet tall. It bears very heavily, usually in the winter time. Needs full sun and good drainage. Trees are fast growing and bear fruit in 2 to 3 years.