Scope of the Work
Definitions are difficult enough to make in themselves; the application of them to a disparate group of individuals, the composition and nature of which changes across the centuries in two countries, is even more so. In the present work therefore the terms of our title have been liberally interpreted. No distinction has been drawn between those who made and those who retailed instruments as many, if not most, of our subjects did both. No sharp line has been drawn either between inventors and makers. Inventors who retailed their inventions, even if they had them made by a third party, are here described along side those who produced their own devices.
In the bibliographies generally all a subject’s publications that we have been able to find, whether they relate to instruments or not, are listed. In the case of individuals who combined the publication of maps and charts with the making or retailing of instruments however, individually published maps, charts and engravings are not listed, although general catalogues including both instruments and maps are. In the case of clock- and watch-makers who also made some related instruments, only publications relating to their instrument production have been recorded.