Copy letter from Lord Kelvin, [William Thomson], to General Sir Francis Walter de Winton Kelvin will be much obliged if Winton will place the enclosed card of invitation [to the forthcoming Soirée] before their Royal Highnesses the Duke and Duchess of York, and express to them on behalf of himself and the Council the great gratification it would give the Society if their Royal Highnesses would honour them with their presence. 16 May 1895