2. Thomas Simpson (a name venerated by every geometer) was one of the scientific men consulted by the committee appointed to decide upon the plans for Blackfriars Bridge, in 1759 and 1760.
"It is probable," says Dr. Hutton, in his Life of Simpson, prefixed to the Select Exercises, 1792, "that this reference to him gave occasion to his turning his thoughts more seriously to this subject, so as to form the design of composing a regular treatise upon it: for his family have often informed me that he laboured hard upon this work for some time before his death, and was very anxious to have completed it, frequently remarking to them that this work, when published, would procure him more credit than any of his former publications. But he lived not to put the finishing hand to it. Whatever he wrote upon this subject probably fell, together with all his other remaining papers, into the hands of Major Henry Watson, of the Engineers, in the service of the India Company, being in all a large chest full of papers. This gentleman had been a pupil of Mr. Simpson's, and had lodged in his house. After Mr. Simpson's death Mr. Watson prevailed upon the widow to let him have the papers, promising either to give her a sum of money for them, or else to print and publish them for her benefit. But nothing of the kind was ever done; this gentleman always declaring, when urged on this point by myself and others, that no use could be made of any of the papers, owing to the very imperfect state in which he said they were left. And yet he persisted in his refusal to give them up again."
In 1780 Colonel Watson was recalled to India, and took out with him one of the most remarkable English mathematicians of that day, Reuben Burrow. This gentleman had been assistant to Dr. Maskelyne at the Royal Observatory; and to his care was, in fact, committed the celebrated Schehallien experiments and observations. He died in India, and, I believe, all his papers which reached England, as well as several of his letters, are in my possession. This, however, is no further of consequence in the present matter, than to give authority to a remark I am about to quote from one of his letters to his most intimate friend, Isaac Dalby. In this he says:—"Colonel Watson has out here a work of Simpson's on bridges, very complete and original."
It was no doubt by his dread of the sleepless watch of Hutton, that so unscrupulous a person as Colonel Watson is proved to be, was deterred from publishing Simpson's work as his own.
The desideratum here is, of course, to find what became of Colonel Watson's papers; and then to ascertain whether this and what other writings of Simpson's are amongst them. A really good work on the mathematical theory of bridges, if such is ever to exist, has yet to be published. It is, at the same time, very likely that his great originality, and his wonderful sagacity in all his investigations, would not fail him in this; and possibly a better work on the subject was composed ninety years ago than has yet seen the light—involving, perhaps, the germs of a totally new and more effective method of investigation.
I have, I fear, already trespassed too far upon your space for a single letter; and will, therefore, defer my notice of a few other desiderata till a future day.
T.S.D.
Shooter's Hill, Dec. 15. 1849.