Answer :
Final answer:
The dial indicator is a precise measurement tool on a caliper used to gauge small displacements. It is akin to instruments like heliometers or vernier scales in surveying, which allow for meticulous calibration and reading for precise measurements.
Explanation:
The dial indicator on a caliper is a device used to precisely measure the displacement along the instrument's scale between marked graduations. In the broader context of engineering and surveying, measuring devices like calipers, heliometers, telescopes, and leveling instruments are critical for obtaining accurate measurements. For example, in the case of a heliometer, which is used for measuring small angular distances or the diameter of celestial objects, the object-glass can be divided and the halves moved apart to measure the distance between two images precisely. The dial indicator would be analogous to the mechanism that measures the separation of the two semi-lenses in a heliometer.
Surveying instruments as described utilize intricate mechanisms and scales to provide precise measurements. The vernier scale, for instance, is common in calipers, allowing for the measurement of internal and external dimensions and depths to a higher degree of accuracy. Just like in the description of the observatory instrument's circle, made with the utmost precision, the dial indicator on a caliper similarly represents the peak of mechanical precision, allowing for fine measurements between the secondary graduation lines.
In differential leveling, the precision of measurement is critical. The surveyor's instrument, placed halfway between two points, measures the height of a rod positioned at different locations to determine the elevation change. The readings taken are akin to how a dial indicator would measure minute differences in position. Each piece of equipment, whether it's for surveying land or studying the stars, relies on meticulous calibration and reading of scales to provide accurate data.
