Credit: ©The Royal Society
    Image number: RS.11628

    Reflecting prism

    Object type
    Archive reference number
    height (object): 145mm
    width (object): 288mm
    depth (object): 250mm
    Content object
    Reflecting prism for use with a spectroheliograph in making observations of solar spectra.

    The astronomer John Evershed FRS (1864-1956) commissioned this glass with the aid of Royal Society grants for the purpose of solar observation at his private observatory in Ewhurst, Surrey. The prism was then transferred for use at the Royal Greenwich Observatory at Herstmonceaux Castle in 1953, before being returned to the Royal Society.

    The instrument’s box is labelled with Dymo-style embossed tape: ‘7 x 10 INCH PRISM BELONGING TO ROYAL SOCIETY EX EVERSHED’.

    John Evershed FRS (1864-1956) British astronomer, was elected a Fellow of the Royal Society in 1915.
    Object history
    This prism was purchased, apparently with the support of a Royal Society grant from the Council Urgency Fund:

    Meeting of Council, 29 October 1925: “Council considered an application from Mr. J. Evershed for £110 for a 6-inch reflecting prism for use with a spectroheliography. Resolved – That £110 be granted Mr. Evershed from the Government Grant Council Urgency Fund.”

    Council Minutes Printed (CMP) v.12 1920-1926 p.297
    Meeting of Council, 14 June 1928: “With reference to Minute 10 of October 29, 1925, the Secretaries reported that it had proved impossible to obtain a 6-inch reflecting prism for the sum of £110 originally granted to Mr. J. Evershed, but that Mr. Evershed had now heard of a piece of glass from which a suitable prism could be made for the sum of £140. Resolved – That a supplementary grant of £30 fron the Government Grant Council Urgency Fund be made to Mr. Evershed for the purpose in question.”

    Council Minutes Printed (CMP) v.13 1926-1932 p.101
    A paper label notes the object’s eventual [1990s?] return to the Royal Society:
    ‘From S P Worswick Royal Greenwich Observatory Maddingley Road Cambridge CB3 0EZ’.
    Powered by CollectionsIndex+/CollectionsOnline