Armsby was internationally renowned for creating an animal respiration calorimeter, which increased efficiency of cattle feeding, in 1901.[1] This nutrition experiment station enabled Armsby to determine how much energy beef cattle and sheep derived from a given food source, measuring respiration, feed intake, water intake, and excrement.[9] The device was based on a design by Wilbur O. Atwater, originally intended for human nutritional research.[3] The first device of its kind in the world,[4] the Armsby Calorimeter attracted visitors from all over the world and bolstered Penn State's reputation.[5]