http://b4hntuy3fimfh2227vf4f74emnya7p35i5brtqujs6leqvtclfwvjbqd.onion/doc/physics/diamonds-crookes/The%20Project%20Gutenberg%20eBook%20of%20Diamonds,%20by%20William%20Crookes..html
Williams, [7] General Manager of the De Beers Consolidated
Mines, and the Managers of neighbouring
mines, did their utmost to assist
me in my inquiries and to ply me with
valuable information. I had full access to
all the workings, above and below ground,
and was able to examine at leisure their
stock and take extracts from their books.