Theodolites of 1890

I was looking at the theodolites used by the USC&GS in the 1890s. I am quite curious about field observation procedures and field note recording.

Aa the instrument has 3 microscopes to read the plate, D and R readings, and given 16 sets, how were the data handled on paper.

In the Transcontinental Triangulation of the 39th parallel, the section labeled Abstract of Horizontal angles, I am curious just what was averaged.

I couldn’t find examples of field note recording, assuming they used forms.

And/or manual of how to operate and read the instrument.

The angles are reported to 0.001” and numerous correction values. Just curious to better understand a bit more of what is what.