Author: Jim Bennett

Title: Decem anni mirabiles: 1860-1870

Abstract: This paper surveys the development of the spectroscope in the first decade after its introduction as an instrument of analysis by Bunsen and Kirchoff. An extraordinary sequence of technical elaboration characterised these early years. There was the design of an integrated instrument by Steinheil, the introduction of a comparison spectrum and of a micrometer scale presented in the field of view, the concept of the prism train, and its automatic adjustment to minimum deviation for the portion of the spectrum under scrutiny, the use of a diffraction grating as an alternative to a prism, the invention of the direct-vision instrument and its application to the microspectroscope, and the 'commodification' (is that a word?) of the instrument through a range of adaptations to customer's needs from simple 'student' instruments to specialised tools for laboratory and observatory use. No prior instrument was the subject of such frantic and fruitful development at the very beginning of its life. How was this possible and what does it teach us about the economy of instrumentation in the 1860s?