Horsehair wrapped around an invitation card from Miss Slater to Mr Herschel.

This invitation card comes from a 15-drawer cabinet found in the Herschel family home in the 1950s. The contents of this and a similar cabinet seem to suggest that they were used by successive generations of the family to store specimens, material and apparatus for carrying out experiments.

Miss Slater does not appear feature in any extant Herschel correspondence which could mean this card predates William's discovery of the planet Uranus in 178 (since it is only after this point that the family begin to keep everything). Alternatively she may have simply been regarded as unimportant by those family members in charge of selecting what to keep. Another indication that this dates from the Herschels' days as musicians in Bath, however is the horsehair which is and was commonly used in the bows of string instruments such as the violin but has no readily use in astronomy.