Dollond's Achromat Patent Dispute

British Journal of Photography, 25 August 1972, Vol. 119, p. 717

Letters to the Editor: ‘Dollond’s (Dolland’s) Achromat Patent’ From Mr R. D. Wood

Dear Sir Recently this journal has published articles and a letter concerning my researches in the legend that J. B. Reade allegedly carried out photographic experiments before 1839. I had hoped that it would be clear that the story of Reade’s alleged work was only of historical significance because of the part it played in the calotype patent lawsuits of the early 1850s — the unsubstantiated story of his uncommunicated experiments supposed to have been carried out before 1839 could have no significance in photographic history. There can never be any point — as some have done — in claiming ‘priority of invention’, even if the case had been proved, for work that was uncommunicated and therefore of no influence. It is therefore with something like dismay that I read the letter from Mr C. O. Harvey in the Journal of 11 August [1972] under the heading Achromat Priority, calling attention to claims ‘that the achromatic lens was not invented by John Dolland [sic] around 1758 but by an Essex man, Chester Moor Hall, as early as 1733’. Yes, Mr Harvey, there are indeed such claims, and there certainly is a comparison to be made with those regarding J. B. Reade. Both legends have depended upon the most inadequate evidence, and both arose during disputes over licences for patents. My dismay concerning Mr Harvey’s letter, and the editor’s selection of the heading, arises from the issue being raised in the form of a claim for Hall’s priority of invention. When such issues are raised they need, I feel, to be dealt with — yet I wonder if discussion on these questions is not self–defeating? It should not be the intention of historical research to investigate priority claims of inventors; the endless wrangles concerning such claims are generally meaningless and historically worthless. But is spite of this stricture, the Hall legend is worth discussing, like that of Reade, because in involves some significant events of the past concerning legal conflict over patent licences. Mr Harvey may be interested to know that, mainly through my work on J. B. Reade, a project has grown up in the last few years on John Dollond’s patent. The interest in this is due, not to any rather pointless priority claim for Hall, but concerning the state of the optical trade at the time of the dispute over the patent in the late 1760s. Litigation over the patent became a test case in patent law, and even in recent years the ruling has been quoted. It is astounding to discover that, in spite of the case being quoted in courts for almost two hundred years, the documentary basis for the ruling — see for example that given in Halsbury’s Laws of England, 1960 — is extremely inadequate and not even contemporary with the case. Just as with my work on J. B. Reade and the calotype patent lawsuits of the early 1850s, the Dollond patent has involved laborious searching of legal records; lacking both time and money it will be a matter of years before I am in a position to satisfactorily complete the work, but without going into the intricacies the following can be stated:

John Dollond took out a patent for the invention of an achromatic lens in 1758. After he died in 1761, the licence was in the hands of his son, and it was not long before a group of London opticians came into conflict with the son about this, and a petition was presented to the Privy Council against the patent in 1764. In legal actions during the following three years, it was alleged by William Eastland, one of the opticians involved in the legal action brought by Dollond’s son, that he and James Ayscough (then deceased, but who had had a shop in Ludgate Street, London) had made lenses on a principle suggested to Ayscough by Hall. Furthermore, he alleged that they had sold telescopes fitted with these lenses in 1753 and the following years before Dollond’s patent was sealed. [1]

In the circumstances in which this allegation was made, I think that probably little reliance can be put on it. But for anyone who wishes to engage their minds with priority disputes, I would recommend that they search for contemporary evidence that such alleged sales were made from 1753 to 1758: for it is only in this way that any supposed invention by Hall of an achromatic lens could assume historical significance. John Dollond’s work and publications were certainly of influence on his contemporaries. His achievement was the hardest task of carrying theory and experiment through to the practical production of lenses free from chromatic (and spherical) aberration, coupled with successful commercial production and sale. Dollond’s business was an influential landmark in the history of optical instruments. R. D. Wood. Bromley

1 Note added in 2003: further work by the author on the opposition in the 1760s to Dollond’s patent ( ‘Making object–glasses of refracting–telescopes, by compounding mediums of different refractive qualities’, Patent No. 721 of 19 April 1758) mentioned in the above published letter was not pursued, and research notes on the subject were passed to another person in the late 1970s. The patent case referred to is Dollond v Champneys and Others, Trinity term 1765, for which the Court of Chancery records at the Public Record Office (National Archives) are as follows: Chancery Bill & five Answers C12/1956/D19; Chancery Affidavits C31/157/179, C31/164/108; Chancery Decrees & Orders C33/423 part ii/460, C33/423 part ii/687, C33/425 part ii/451v, C33/427 part ii/296.

British Journal of Photography, 25 August 1972, Vol. 119, p. 717