In 1769, his nephew John Troughton Junior, after completing his apprenticeship with his uncle, set up in business for himself.
His work at that time was mostly providing a service to other craftsmen in the difficult skill of dividing circles by hand for navigation, surveying and astronomical instruments.
William Simms completed his goldsmithing apprenticeship in 1815 and set up business as a maker of marine compasses.
Having completed this work, he wrote a paper for Edward Troughton describing his new method of dividing which was more accurate than an engine and quicker than using a roller.
To try to make his theodolites less susceptible to field conditions Everest proposed a new pattern with a lower centre of gravity.
Optical glass technology allowed larger lenses to be made and these were sourced from French and German makers such as Guinand and Merz.
Slow delivery appears to have happened a lot and seems to have been partly due to insistence on precision but also the volume of business being undertaken.
[2] Towards the end of this period other countries such as France, Germany and the United States were able to make instruments themselves so Troughton & Simms made more of their product for the British market.
Undated advertisements from this period include the claim that "in fifteen years our output of levels and theodolites alone was 23,000".