The letter sent by the Royal Society to the London optician, John Marshall, in 1694, commending his new method of grinding, has been reprinted, and referred to, in recent years. However, there has been no comprehensive analysis of the method itself, the letter and the circumstances in which it was written, nor the consequences for trade practices. The significance of the approval by the Royal Society of this innovation and the use of that approbation by John Marshall and other practitioners (...) are examined. Gaps in existing accounts of Marshall's method are partly remedied by supplementing surviving written materials with accounts of contemporary, and present-day, trade practices based on his method. The reasons why Marshall and his contemporaries failed to record his method and specify his improvements are discussed. The reactions of the Spectacle Makers' Company and its more prominent members, both to the innovation itself and to the Royal Society's letter, are analysed. The impact of the new technique on contemporary and later opticians is described. (shrink)

The paper examines the structure of the mathematical instrument making trade in London from the mid-sixteenth century to the opening of the Hanoverian era. This analysis of the trade is primarily based on evidence drawn from contemporary advertising. A distinction between informal editorial recommendations and advertising per se is made. It is concluded that up to the mid-seventeenth century mathematical instrument makers worked in either wood or metal. After that date a growing number of workshops advertised that they manufactured in (...) all media. Advertising was aimed at informing professional users from whom particular instruments could be purchased, but not on informing customers in specific terms of the range of instruments manufactured. It is concluded that until the early eighteenth century most mathematical instruments were commissioned. Only towards the end of the period is there evidence of over-the-counter sales, and advertising aimed at encouraging the growing consumer market to buy mathematical instruments for the practice of science as a social or recreational activity. (shrink)

SummaryRecent studies have confirmed the traditional attribution of the invention of the balance barometer to Sir Samuel Morland. Two contemporary references to a 1678 printed pamphlet describing the invention are known but no copy has been located. This paper prints a seventeenth century manuscript copy of Morland's description of his balance barometer. The commentary outlines Robert Hooke's role in the invention. Morland's analysis of the mode of action of the instrument is considered in the light of contemporary comprehension of the (...) barometric phenomennon. (shrink)

In 1736 Colin MacLaurin, Professor of Mathematics in the University of Edinburgh petitioned the Town Council for permission to erect an astronomical observatory in the College to broaden the research and teaching base of the University. After MacLaurin's death, the Town Council and University Senate, more concerned with the promotion of the Infirmary and associated medical teaching, took no further action. The funds raised by MacLaurin were lent to his successor, and largely dissipated. In 1776 the balance was transferred to (...) the proposed Calton Hill Observatory. This private scheme was to be financially self-sufficient, generating income from the casual visitor and fees charged to students. It too failed. Funds were wasted on unnecessary architectural elaboration, the Town Council failed to meet their financial obligations, the University acquiesced in the total inactivity of the Regius Professor of Astronomy, whilst the commercial management-base of the Observatory vitiated any serious scientific activity. (shrink)