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.
1 India Tree Decorating Colors are made from highly concentrated vegetable colorants. They contain no corn syrup or synthetic dyes. 2  Use them to color icing in rich jewel tones or soft pastels.  With the primary colors - yellow, red, and blue - you can create a full spectrum. Try the following combinations: yellow + blue = green; blue + red = purple, lavender, and violet; red + yellow = gold, orange, and terra cotta.