Hill died of gout on the 21st of November, 1775, at about the age of 59, in Golden Square, and was buried at Denham. Notwithstanding the large sums of money he had made, he died heavily in debt owing to the great expense entailed by the publication of the Vegetable System and his own personal extravagance. His library was sold in 1776-7, and it has already been mentioned that the copyright of the Vegetable System was disposed of by auction.
It is always a matter of difficulty to appraise a man's character, and more particularly is this true of Hill whose character, as Whiston[90] has truly remarked, was so "mixed that none but himself can be his parallel." In the Sleep of Plants the following passage occurs: "There is a freedom of style, and assumed manner peculiar to this kind of correspondence, which would be too assuming in works addressed immediately to the public; and might not unnaturally draw upon the author a censure of self-sufficiency and vanity. This explanation, I hope, will defend me from so unfair a charge: for indeed no one knows more the narrow limits of human knowledge; or entertains an humbler opinion of the returns of years of application." Nothing could be more proper than this, but against it must be set the opinion of men of his own time, as expressed in the quotation on [p. 88], taken from Baker's Biographica Dramatica.
Many estimates of the character of Hill have been put forward, the first of any authority being that of Johnson[91]:—"The King then asked him what he thought of Dr Hill. Johnson answered, that he was an ingenious man, but had no veracity; and immediately mentioned, as an instance of it, an assertion of that writer, that he had seen objects magnified to a much greater degree by using three or four microscopes at a time than by using one. 'Now,' added Johnson, 'everyone acquainted with microscopes knows, that the more of them he looks through, the less the object will appear.'... 'I now,' said Johnson to his friends, when relating what had passed, 'began to consider that I was depreciating the man in the estimation of his sovereign, and thought it was time for me to say something that might be more favourable.' He added, therefore, that Dr Hill was, notwithstanding, a very curious observer; and if he would have been contented to tell the world no more than he knew, he might have been a very considerable man, and needed not to have recourse to such mean expedients to raise his reputation."
If Hill's reputation for lying rests on no surer foundation than this, he must be held acquitted of much that is charged him. In the above quotation the term microscopes must be read lenses; thus Johnson's reason for his opinion is unfortunate and clearly shews, as Bishop Elrington has remarked, that Johnson was talking of things he knew nothing about. This is the more to be regretted since the opinion of a man of Johnson's rank, who was contemporary with Hill, might have biassed the judgment of smaller and later men.
According to Fitzgerald[92], Hill was a "quack and blustering adventurer," the "Holloway of his day," endowed with "cowardice that seemed a disease." This author is, I think, prejudiced, and his estimate appears to be based upon the least creditable of Hill's performances without giving a proper value to the better side of his nature and work. On the other hand the author—a grateful patient—of the short account of the life of Hill[93] went to the other extreme. This account is entirely laudatory, and describes Hill as being little short of a genius surrounded and continually attacked by "envious and malevolent persons" who "did not fail to make use of every engine malevolence could invent, to depreciate the character and the works of a man, whom they saw, with regret, every way so far their superior."
Disraeli[94] speaks of Hill as the "Cain of Literature," and, whilst being fully alive to his "egregious egotism" and other defects of character, he appreciates his worth and recognizes that Hill was born fifty years too soon. Also he gives him credit for his moral courage in enduring "with undiminished spirit the most biting satires, the most wounding epigrams, and more palpable castigations."
The general consensus of opinion, much of which does not appear to have been independently arrived at, is that Hill's nature contained little that was commendable. At the same time his remarkable industry and versatility were recognised. His independent and quarrelsome nature, coupled with his mode of attack and fearlessness in expressing his opinions, made him cordially hated, and caused much that he did to be viewed with a prejudiced eye; for instance, it is generally stated that he obtained his degree of Doctor of Medicine (St Andrews, 1750) by dishonourable means. Mr Anderson, Librarian and Keeper of the Records of St Andrews University, has kindly looked the matter up and informs me that there is nothing whatever to warrant such a statement; the degree was granted according to the practice of the time.
It is important to remember that Hill in his earlier days suffered much from penury, which, to a certain extent, may have embittered his nature. However this may be, he learnt subsequently the advantages conferred by a good income, and was not desirous of becoming reacquainted with his earlier experiences. This may explain much of his peculiar behaviour. Disraeli[95] suggests that, in offering himself as Keeper of the Sloane Collection, at the time of its purchase for the British Museum, Hill was merely indulging in an advertisement. Hill probably was sufficiently shrewd to realize that a ready sale for his wares would obtain so long as he kept within the public eye, and much of his extraordinary behaviour in public may have been merely self-advertisement.
The portrait of Hill prefacing this sketch is after Neudramini's engraving of Coates's portrait (1757); the plant represented is a spray of a species of Hillia, named in honour of Hill by Jacquin.