Level

Today's the day ……………………… to survey

Back at the dig today when I was instructed in the use of this instrument.

For those that have never come across such a thing (like me) it's a Level - an optical instrument used together with a levelling staff to measure the relative heights of objects or marks.   It operates on the principle of establishing a visual level relationship between two or more points, for which an inbuilt telescope and a highly accurate bubble level are used to achieve the necessary accuracy.  It was used on the dig to measure the difference in height between various points along the trench, relative to a base marker.

Now you know as much as I do …………………..!