story of Diamond (pg. 21) -- the quote in the book is from At The Back Of The North Wind, by George MacDonald, a children's book published in 1871.
Anton Seidl (pg. 92) -- Hugarian-born conductor who became conductor of the New York Philharmonic in 1891. He died in 1898.
Robert Ingersoll (pg. 92) -- Lucinda notes that Aunt Emily said he didn't believe in God. Lucinda wonders "a great deal" why, but never finds out. A very interesting Wikipedia article I perused said he was a great orator and spoke on many topics, including agnosticism.
guimp (pg. 142) -- A narrow flat braid used for trimming. Also spelled gimp.
Cornelius Nepos (pg. 131) -- A Roman biographer.
gertrude (pg. 178) -- A type of clothing for infants. More information is online in The Care Of The Baby, by J. P. Crozer Griffith, published 1900.
The princess brought out a lacquered box, and out of this some cigarettes. She lighted one, lay back on the cushions, and smoked. Lucinda had never seen, had never dreamed it even possible that a woman could smoke. It only made the whole ending of that day appear more unbelievable. (pg. 100)