616 THE POPULAR SCIENCE MONTHLY. 



through the soil, accompanied only by a few bits of quartz. Accord- 

 ing to the popular expression, the crystals of the precious stone could 

 be picked out of the roots of the grass when it was pulled up. A 

 diamond of twenty-eight carats was found on the surface of the 

 ground. At some distance from this spot, I have myself seen, on the 

 summit of the ridge between the valleys of the Jequitinhonha and 

 the Rio das Velhas, diamonds in ground-cracks some inches deep, with 

 no other companions than enormous crystals of quartz. Cavities in 

 the rock a few metres away did not contain a trace of diamonds, 

 although they bore identical crystals of quartz. The old miners 

 ascribed the disposition of the minerals they sought in regular veins 

 to the intervention of good genii. It seems as if, at Diamantina, a 

 wicked fairy must have sown the diamonds on the ground according 

 to its caprices; and never were caprices more whimsical and varied. . 

 The diamond there forms only an insignificant part of the gravels, and 

 is in most uncertain proportions. 



The work of washing the diamonds is done wholly by hand. In 

 the first operation, the sands are placed, in portions of two hundred to 

 two hundred and fifty pounds, in a kind of hod or rectangular trough, 

 only three sides of which are inclosed. The hods are arranged by 

 twos, fours, or sixes, by the side of a trough of water about a foot 

 and a half deep, so that their bottoms shall be slightly inclined toward 

 it. A workman, standing in the trough before each hod, dashes water 

 upon the sand in it. The clay and the very fine sands are carried away, 

 and the first separation is made. The larger pieces remaining in the 

 top of the sand are picked away ; the diamond is to be found in the 

 two upper thirds of the mass that is left, the lower part being nearly 

 sterile. The washing is afterward finished in bowls a little deeper 

 and a little more conical than those used by the gold-washers. The 

 washer puts the sand in the bowl and fills it with water ; then by 

 whirling the bowl and shaking it up and down while the sand is float- 

 ing around in it, and being careful to stir it from time to time with 

 his hand, he determines a classification in the order of density. This 

 work is easy if he is washing gold ; for that metal is heavier than the 

 substances with which it occurs, and always goes to the bottom. 



The diamond, however, having a density about three and a half 

 times greater than that of water, and more considerable than that of 

 quartz and tourmaline, but less than that of the oxides of iron and 

 titanium, its constant companions, settles in the middle layers. The 

 washer, after several rinsings, removes the upper particles, hardly 

 looking at them, and, when he has reached a certain level, which his 

 skill recognizes at once, tips his bowl slightly, so as to let the water 

 run off in a thin film, and, perceiving the glittering crystals of the 

 diamond, picks them out with his fingers. The vigilance of the over- 

 seers must be redoubled at this stage, particularly when slaves are em- 

 ployed ; for I know of nothing equal to the skill of the slaves in find- 



