http://b4hntuy3fimfh2227vf4f74emnya7p35i5brtqujs6leqvtclfwvjbqd.onion/doc/physics/diamonds-crookes/The%20Project%20Gutenberg%20eBook%20of%20Diamonds,%20by%20William%20Crookes..html
Bonney, and Miss Raisin. Notes on the Diamond Rock of South
Africa. By W. H. Hudleston. The Parent Rock of the Diamond in South
Africa. By the Reverend Professor T. G.
Bonney. The Presidential Address, by Grove Carl
Gilbert, to the Geological Society of Washington,
on The Origin of Hypotheses.