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Account of a Method of dividino astronomical and other 

 Instruments, ly ocvlar Inspeclioti, &c. 



It would ill become me, in addressing myself to the 

 Members of this Society upon a subject which they are so 

 well enabled to appreciatf, to arrogate to myself more than 

 may be assigned as my due, for whatever of success may 

 have been the result of my long continued endeavours, ex- 

 erted in prosecuting towards perfection (he dividing of in- 

 Strutnents immediately subservient to the purposes of astro- 

 nomy. A man very naturaUy will set a value upon a thing 

 on which so much of his life has been e-^^ended ; and I shall 

 readily, therefore, be pardoned for saying, that considering 

 iome attainments which I have made on this subject as too 

 valuable to be lost, and being enconrao;ed also by the de- 

 gree of attention which the Koyal Society has ever paid to 

 practical subjects, 1 feel myself ambitious of presenting them 

 to the public through what I deem the most respectable 

 channel in the world. 



It was as early as the year 1775, being then apprentice to 

 my brother, the late Mr. John Troughton, that the art of 

 dividing had become interesting to me ; the study of astro- 

 nomy was also new and fascinating; and I then formed the 

 resolution to aim at the nicer parts of my profession. 



At the time alluded to, my brother, in the art of dividing, 

 wa» justly considered the rival of Ramsden ; but he was then 

 almost unknown beyond the narrow circle of the mathema- 

 tical and optical instrument n)ake)'s ; for whom he was 

 chiefly occupied in the division, by liand, of small astrono- 

 mical quadrants, and Hadley's sextants of large radius. 

 Notwithstanding my own employment at that time was of a 

 much inferior nature, yet I closely inspected his work, and 

 tried at leisure hours on waste materials to imitate it. With 

 as steady a hand, and as good an eye, as young men gene- 

 rally have, I was much disappointed at fu.ding, that after 

 having made two points, neat and small to my liking, I 

 could not bisect the distance between them, without enlarg- 

 ing, displacing, or deforming them with the points of the 

 compasses. This circumstance gave me an early dislike to 

 the tools then in use; and occasioned me the more uneasi- 

 ness, as I foresaw that it was an evil which no practice, 

 care, nor habit could entirely cure. Beam-compasses, 

 spring-dividers, and a scale of equal parts, in short, appeared 

 to me little better than so many sources of mischief. 



I had already acquired a good share of dexterity, as a ge- 

 neral workman. Of the different branches of our art, that 

 oi turning alone seemed to me to border on perfection. This 



juvenile 



