The most common and most likely answer to this crossword clue is the 10 letter word THEODOLITE
I've seen this crossword clue in The Guardian
T
H
E
O
D
O
L
I
T
E
More clues leading to the result THEODOLITE
- Roosevelt settled for Republican surveying device
- Use it to survey the back of old limestone circles
- Chap to study fragments of tile with instrument for measuring angles
- Instrument locating diamonds in the limestone
- Kojak perhaps toiled unusually; it helps to check every angle
- Surveyor’s instrument finds diamonds in the grainy limestone
- It enables one to get an angle on the situation
- He toiled to reset instrument
- Surveying instrument, article newly tooled bearing inventor’s origin
Buddy explains!
The straight part
We know that "surveying device" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case surveying device = theodolite.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does THEODOLITE mean?
THEODOLITE noun- A surveying instrument, consisting of a small mounted telescope, used to measure horizontal and vertical angles.