Add MS 88942/1/190

Notes on various subjects. Regarding astronomy, the notebook contains a method for correcting the level of a telescope and remarks on the examination of the spectrum of the sun and of the moon. Mathematical notes deal with cubic parabloa, integrale, 'equilateral hyperbola', lemniscates and longitudes. Further notes include entries on examining diffracted light by passing light focused by a lens across a single hair or a pair of crossed hairs, notes on the study of diffraction, notes on various treatments of glass, various kinds of diffraction-producing arrangements, notes on the idea that a mirror at the bottom of lake would enable the observer to find the 'real tint of the water', an Iceland spar prism that could be a photometer allowing us to combine any two colours, a proposal to 'diminish any drawing' (by pricking its outline with pinholes and then projecting this with a telescope lens using the light of the sun and then tracing), notes on the reflection and the transmission of light in opaque powdered glass, and a comment on the wave theory of light (Talbot probably refers to Herschel’s article on light in the Encyclopedia Metropolitana (1830), 2: 341-582). There are also scattered notes on coloured flames, hardening tallow, magnetic experiments, temperature measurement, 'the doctrine of perfectly hard bodies' (ff. 17-18), a method for correcting the level of a telescope (f. 18), a one-line note that Herschel has some important remarks on 'the identity of the nervous fluid with electricity' (f. 19), notes on epicycloids (formed by a circle rolling on another of twice the diameter), a study of the shapes obtained by rotating a circle about an axis (annulus, closed annulus, involved annulus, etc), a note on capillary action between two glass plates, more on geometrical proofs involving revolving 2-D shapes, notes on Chasles’ work on cones, notes on a geometric proof concerning an ellipse, notes on 'a straight line remains unaltered when viewed from any distance', more notes on crystals and optical properties of liquids, thoughts on invisible ink (see also Add MS 88942/1/191 and Add MS 88942/1/193), notes entitled 'R inst.' [Royal Institution], a note to 'examine spectra produced by various substances using a flame of portable gas', and notes on the optical properties of drops of milk and other liquids under a miscroscope and between glass. Talbot suggests that one could use a micrometer to measure bands in the spectrum. Further notes include entries on compound prisms, notes on fusible metal run between two glasses that makes a beautiful mirror, and notes on liquid between plates of glass. More notes deal with experiments at the Royal Institution on spectra, on longitude, and a note that Faraday showed Talbot the flame of Lithium (f. 60) - another note states that Talbot examined the spectrum of this flame. Notes on a pendulum between two electro magnets, notes on an Experiment at the Royal institution, and spectral analysis of iodine vapor. These entries are followed by notes on electric spark, more notes on spectra and capillaries and crystals, notes on diffraction, notes on sulphur, notes on various chemical experiments, and crystallization.

Notebook started: 12 Oct 1831, London. Designated 'I' on outside and inside front cover.