Microscopical Examination of Specimens of 



A. "Sand from depth of 32 foct, in which gas was struck, 

 . L6, L868." 



This is a sand of an extremely fine texture, light grayish in 

 color, and when viewed with the unassisted eye is seen to have 

 1 through it small black particles of matter. On account 

 of the occurrence of the inflammable gas at this point, and the re- 

 port that, from a similar well near by, fragments of blackened, 

 wood-like material had been ejected, I was persuaded to ex- 

 amine these small dark-colored specks otherwise than micro- 

 scopically, especially as that instrument had revealed no trace 

 of organic structure of any kind in them. On heating one of 

 them on a strip of platinum foil over a spirit-lamp, the black 

 tint was burned off, leaving a white ash. This appeared to in- 

 the presence of organic matter, and a further examination 

 proved it beyond doubt. A drop of pure oil of vitriol was 

 heated in a watch-glass and a small fragment of potassium di- 

 chromate dissolved therein. To a minute portion of this liquid 

 one of the black grains was added and heat applied ; imme- 

 diately the black particle was attacked, a gas given off, which 

 was, without doubt, carbon dioxide, and the orange color of the 

 liquid changed to a green, which was made apparent by pla- 

 cing the glass slip upon which the reaction took place over a 

 t of white paper, showing that the dichromium trioxide sel 

 bv the action of the oil of vitriol had been convened into 

 aenromium trioxide by the organic matter. This proves 

 the small black particles to be carbonaceous, and 1 have de- 

 tailed the proc L to arrive at this result, as it is one which, 

 familiar as it is to chemists, is not sufficiently well known to Dat- 

 um' ' aerally, and it can, at the same time, be very con- 

 veniently employed when examining small quantities of matter, 



: under the microscope. No other tra >f organic remains 



of any kind was detected in this specimen. 



]'.. " First .-harp sand struck at a depth of l'- 1 feet," 



This specimen © I alm< I entirely of a clean, transparent, 

 and colorless quartz sand, of which the particles are sevenJ 



