. Quarterly journal of microscopical science . SamuelHlGHLEY, , , &c. Part I.—Instruments of Micro-Mineraloyical Research. For the preliminary inquiry as to the general features of amineral mass, I arranged an instrument that should allow ofits free movement in all directions, and that might be left inany position during a prolonged or interrupted examinationby means of the ordinary hand or pocket lens ; this is deli-neated in fig. 1, by which its construction will be readilyunderstood. To a firm base a ball-and-socket motion isattached ; from the upper part of the ball arises a ci
. Quarterly journal of microscopical science . SamuelHlGHLEY, , , &c. Part I.—Instruments of Micro-Mineraloyical Research. For the preliminary inquiry as to the general features of amineral mass, I arranged an instrument that should allow ofits free movement in all directions, and that might be left inany position during a prolonged or interrupted examinationby means of the ordinary hand or pocket lens ; this is deli-neated in fig. 1, by which its construction will be readilyunderstood. To a firm base a ball-and-socket motion isattached ; from the upper part of the ball arises a circularstem on which fit three right-angled arms, capable of rotatinground their axis to any position, and then being clamped by abroad circular stage that screws on to the axial stem ; throughthe top of each arm a square rod passes, likewise capable ofbeing clamped at any point by little nuts ; on the end of eachrotates a disc, studded with three pins, which may be usednaked or clothed with corks, according to the nature of the Fiff. body under examination : a telesc()[ic universval movement-stand for the lenses completes this arrangement. The stop-VOL. IV. U 278 CONTIMBUTIONS TO MICKO-MINERALOGY. plate of the lenses may be conveniently fitted with a smallmoveable Tourmaline annlizer. A stouter stand and stem,carryinj? a Leesons or Schmidts goniometer, may be used inplace ol the lens, for measuring the angles of large crystals. Fig. 2.
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