670 PHILOSOPHICAL TRANSACTIONS. [aNNO 174g. 



tonian theory, as in the Philos. Trans. N° 482, Mr. D. proceeded to examine 

 the mean motion of the moon, of her apogee, and nodes, to see whether they 

 were well represented by the tables for any considerable number of years, and 

 whether he should be able to make out that acceleration of the moon's motion 

 which Dr. Halley suspected in the Phil. Trans. N° 218. 



To this end Mr. D. compared several eclipses of the moon observed by 

 Tycho Brahe, as they are set down in his Progymnasmata, p. 1 14, with Mr. 

 Dunthorne's tables, and found them agree full as well as could be expected ; 

 considering the imperfection of his clocks, and the difficulty there mast com- 

 monly have been in determining the middle of the eclipse from the facts ob- 

 served, as published in his Historia Coelestis. Indeed the small distance of time 

 between Tycho Brahe and Flamsteed rendered Tycho's observations but of little 

 use in this inquiry. 



The next observations that occurred, were those of Walther and Regiomon- 

 tanus, which being at double the distance of time from Flamsteed that Tycho's 

 were, seemed to promise some assistance in this matter : on comparing such of 



this capacity he pursued his studies, which had been already extended to mathematics, with in- 

 creasing activity, and considerable success. Having arrived at maturity, and stored his mind with 

 various kinds of knowledge, he undertook the management of an academy at Coggeshall, in Essex, 

 for preparing young gentlemen for the university. 



From this situation, however, he was called by his kind master, who procured him the butlership 

 of his college, and engaged his assistance in his various scientific and mechanical pursuits, particu- 

 larly in the construction of the amazing hollow sphere of 18 feet diameter, which it is well known 

 Dr. Long erected at Pembroke Hall. During this time Mr. D. published his treatise on the moon's 

 motions, and his several papers in the Philos. Trans. Vols. 44, 46, 47, 52. It was also said that 

 Dr. Long kept a printing press in his house, with which Mr. D. actually printed all the first volume, 

 and part of the second, of the doctor's astronomy. 



On the death of his patron, in 1770, by whom he was always treated with the greatest kindness, 

 and with whom he always lived in the strictest intimacy and friendship, he found himself named in 

 the doctor's will, as one of his executors, an office which he discharged with every possible atten- 

 tion to the honour of his benefactor. Mr. Dunthorne retained his office in the college till his 

 death, which happened March 3, 1775. He had lived in habits of intimacy with many scientific 

 men in the university ; and, when he died, left behind him a character of integrity in all his con- 

 duct ; of kindness to his poorer relations, many of the younger branches of which he settled in the 

 world ; and of sincere respect among those who obtained his acquaintance. It seems Mr. D. left 

 behind him a great number of valuable manuscripts and drawings, most of which were inconside- 

 rately burnt soon after his death, as waste paper. Their value is conjectured from some portions 

 which remain, and which, by lying in another place, escaped the fate of the former. The writer 

 of this has seen a manuscript volume in Mr. D.'s own hand writing, of ob.servatioris, taken for the 

 purpose of forming a map of Cambridgeshire, at all the principal places in that and the neighbour- 

 ing counties. The manuscript is written with the greatest neatness and apparent accuracy; but the 

 map, if it ever was finished, has doubtless been destroysd. Mr. D. was also at different times con- 

 sulted and engaged on the drainage of the fens ; and the locks on the river Cam, near Chesterton, 

 were built under his direction. 



