APPARATUS FOR EXAMINING ORES.

Te Aroha News, Volume VI, Issue 300, 19 September 1888, Page 2

APPARATUS FOR EXAMINING ORES.

An apparatue for examining 1 rocks, to determine whether they contain metallic ores, has been patented in California, of which the following account is given :—: — One pole of a battery is connected with one terminal of a telephone receiver by means of a wire in the usual way, the remaining pole of the battery being connected by a conductor with a similar brush having a like handle. In examining rocks in situ, the two brashes forming the terminals of the conductors connected with the telephone and battery are drawn along the face of the rock, while the telephone is held to the ear of , the operator. If the rocks contain metnl they conduct the current, an 1 the movement of the brushes along the , rough face of the rock causes variations therein, which are audible through the telephone, there being no sounds produced "when the rock contains no minerals. In examining detached portions of rock, the latter are placed upon a conducting plate connected with the tele- : phone through the battery, and the brush ] at the other terminal is touched to the ! rock, which, if it contains metal {or metallic ores, will cause sounds to be heard in the telephone. Instead of using- the conducting plate, the fragments of rock may be examined by being placed upon insulating material, and bringing both brashes in contact with^each specimen. Otlfer means of indicating the passage of the current may be employed instead of the tolcphone receiver, as the operator mny place the conductors oujhis tongue and note the sensations duo to fclie completion of the circuit, or a gulvanoineUr may bo employed, or a paper saturated with salt, which will be decompose » by I fro current,, making mmks ou the paper. The telephone receiver, however, is preferable from its portability and effectiveness and the ease with which it is- manned.