Kelly B. answered 07/30/19
Caring tutor who wants to see all children succeed!
Lethuel isn't a word that you will find in any dictionary and there will be no useful search results for the word because it is likely that "lethuel" was a typo or an OCR error (Optical Character Recognition) from scanning or poor transcription especially since the 1901 census was filled in by hand. The best way to know for sure would be to find a copy of the census online but i'm pretty sure that you are correct to assume that lethuel is a term used for a demonstrator or part time lecturer.
Hope this answer helps you some. If you have any other questions or comments about this please feel free to message me.