6 2 o THE POPULAR SCIENCE MONTHLY. 



the region. The constant association of this precious stone with those 

 minerals causes me to believe that it has been brought, like them, 

 from the depths of the earth in the condition of a volatile compound, 

 and that it owes its crystallization to a dissociation produced under 

 the action of heat and a considerable pressure. Now, what is this 

 volatile compound ? 



As to the oxides of iron and titanium, together with what takes 

 place in volcanoes, the synthetic experiments of M. Daubree leave no 

 doubt that they have come up as chlorides and fluorides. May the case 

 not be the same with the diamond ? Its presence in the midst of a 

 crystal of anatase lends support to this hypothesis. This is, it is true, 

 only an hypothesis ; but it is an hypothesis based on the observation of 

 phenomena in which I have taken analogy for my guide. Far be it 

 from me to assume that I have resolved the problem. I shall be well 

 satisfied if I shall ever be able to raise the corner of a veil which 

 more fortunate and more skilled men than myself will, I am convinced, 

 eventually remove completely. 



It is very difficult to estimate the quantity of diamonds furnished 

 by Brazil. Between 1772 and 1793 the royal treasurer received 877,717 

 carats of diamonds, or about 38,000 carats a year. At least as many 

 more were stolen or smuggled away. This would make the annual pro- 

 duction in round numbers about 80,000 carats ; if we assume this aver- 

 age for a total period of a hundred and fifty years, we reach the figure 

 of 12,000,000 carats, or nearly 2,400 kilogrammes (6,000 pounds), or a 

 volume of seven or eight hundred quarts. It is impossible to calculate 

 even approximately the total value of these stones. Generally, the dia- 

 monds of Brazil are small ; stones of fifteen or twenty carats are rare ; 

 and the Star of the South, a stone which was found in the western 

 part of the province, at Bagagem, is the only one of them that calls 

 for a special mention. This diamond weighed, in the rough, 254*5 

 carats, and, after being cut, 125 carats. Finds like this are very rare ; 

 and I know of miners who have washed and washed over the cascalhos 

 of Bagagem for twenty years, without having found a second Star of 

 the South, or even a single diamond of value. They are still, how- 

 ever, far from giving up the search. The total production of Brazil 

 in 1880 hardly exceeded sixteen kilogrammes, or forty pounds (about 

 80,000 carats). In the same time, the mines of the Cape yielded 

 2,000,000 carats. The Brazilian diamonds, however, have a very 

 marked superiority in luster and beauty, so great that they have often 

 been taken for Indian brilliants. 



