Anniversary Address. 15 



seen, thatin 1837, Sir David Brewster pointed out thatthe Diamond 

 possesses strata of different refractive powers ; and he uses this 

 as a strong argument for its vegetable origin — the changes of 

 refraction, and, consequently, the density in parts and hardness 

 ia the san-e crystal, being due to the action of the gases 

 imprisoned in an expansive mass. 



If we now consider the relations of the Diamond to the rocks 

 in which it is found, we shall see how great or how little is the 

 dependence upon them for its origin. 



A statement was made in " Nature," February, 1870, p. 363, 

 respecting the finding of a Diamond in granite in the neighbour- 

 hood of Prague. It is described as exceeding in hardness the 

 Brazilian diamonds. It was suggested to be Zircon, but this 

 Dlaschkowitz stone appears to be a veritable diamond. Its 

 occurrence in granite was also mentioned in the Chemical Journal. 

 The statement came from Professor Sehafarik, who sent it to the 

 Bohemian paper " PoZ/i^i^." On such authority it was received 

 but not believed as authentic. 



It was not till I found mention of it in an Italian publication 

 that I discovered the mistake that had been committed. In a 

 notice, under the head " Scoperta di Diamanti in Boemia" in No. 

 6 of the JBollettino of the Reale Gomitato Qeologico d' Italia, pub- 

 lished in June, 1870, p. 175, we read " Fecesi questa scoperta sul 

 finire dello scorso anno nelle vicinanze di Dlazkovic, villaggio 

 post© tra Bilin e Lobositz, in Boemia, dove existe un giacimento 

 di sabbie Granatifere lavorate per 1' estrazione dei piropi, varieta 

 di granato di un bel color rosso. Commista al prodotto della 

 lavatura di ques'e sabbie, rimarcossi dai lavoratori una piceola 

 pietra sconoseiuta, durissima, e di color giallo-verdastro, che sot- 

 toposta ad esame si riconobbe essere un piccolissimo diamante 

 del peso di 57 milligrammi ed in forma di esaedro a spigoli ro- 

 tundati. Dopo di quest' epoca altri diamanti di simil fatta si ri- 

 trovarono, benche assai di rado in quelle sahhie granatifere 

 Quantunque sia questa scoperta di ben poca importanza, pure 

 crediamo bene di segnalarla, essendo indubbiamente questo il 

 primo giacimento diamantifero che in Europa siasi trovato.^^ 



From this we learn that these diamonds were not found in granite, 

 but in a garnetiferous sand, which is a new ia,ciiov Europe but not 



