Crescograph and Auxanometer are:

Crescograph and Auxanometer are both instruments used to measure plant growth, but they differ in their specific functions and mechanisms:

Crescograph:

Function: A crescograph is designed to measure the growth of plants, particularly the rate of growth.
Mechanism: It operates by magnifying the growth of a plant's cells, often using a series of levers to amplify small movements. Modern crescographs can include electronic sensors and systems to record growth over time.
History: The crescograph was notably developed by Sir Jagadish Chandra Bose, an Indian biophysicist, in the early 20th century. His work helped demonstrate that plants are sensitive to external stimuli and have their own form of "nervous" responses.
Application: It is used in botany and agricultural research to study the effects of various factors on plant growth, such as light, temperature, and chemicals.
Auxanometer:

Function: An auxanometer measures the growth in length or height of a plant.
Mechanism: It typically consists of a lever or pulley system attached to a growing plant. As the plant grows, it moves the lever or changes the position of the pulley, and this movement is translated into a measurable change on a scale or dial.
Types: There are several types of auxanometers, such as the arc-auxanometer, which uses an arc-shaped lever, and the direct reading auxanometer, which records growth directly without the need for magnification.
Application: Auxanometers are often used in educational settings, as well as in research to measure the effects of different treatments or conditions on plant growth over time.
In summary, both instruments are crucial in plant physiology studies, with the crescograph focusing on growth rates and microscopic changes, while the auxanometer measures changes in length or height.