177 

 Instructions for using: our Universal Mining Transit. 



Instrument and lamp target attach to their tripods in the manner described on page 46. To secure an 

 equal height of lamp target and instrument above tripods a slotted disk, provided with the instrument, must be 

 placed and tightly screwed between the head of the leveling screw and the leg of the instrument's stand on the 

 side where the lower tangent screw is situated. This is done to afford a fixed leg, so that when the instrument is 

 leveled up, it be always of the same height. The lamp also has a fixed leg and two leveling screws and when 

 leveled up is of the same height as the transit. When interchanging, care must be taken not to disturb the 

 tripods, and to place the fixed legs of both instrument and lamp in the circular shaped receptacle provided for 

 them in the sliding piece of each tripod. Instrument and lamp will then be leveled up, each with 2 leveling 

 screws, after which their relative height and position above ground will be again the same as before they were 

 interchanged on their tripods. Lamps and targets must be manipulated as explained under Mining Transit No. 7. 



A concentric groove is provided near the bottom of the center part of the trivet of the instrument and lamp, 

 around which a fine wire may be fastened whenever their distance apart must be measured. 



All horizontal angles measure from the center of the instrument, whether the telescope is in the normal 

 or in the excentric bearings. All vertical angles measure from the center of the telescope's axis of revolution 

 respectively. The distance between the centers of both bearings must be determined and correction must be 

 applied whenever, in measuring vertical angles, the telescope is in the excentric bearings. A small hole drilled 

 in center on top of the transverse axis serves for centering the instrument under a given point by means of a 

 plumb bob suspended from the roof when the telescope is placed horizontal. 



The brass counterpoise permanently fastened to the instrument in front of the main vernier serves to 

 balance the weight of the excentric bearings. 



The large counterpoise of lead is to be fastened against the brass counterpoise by means of the milled 

 headed screws, whenever the telescope and its attachments are used in the excentric bearings. The small 

 counterpoise of lead is to be placed on the instrument when the striding level is to be used over the excentric 

 bearings. Both weights are slotted to facilitate this operation. 



The large counterpoise shown in the cut is not quite sufficient to balance the weight of the telescope in 

 the excentric bearings, but as the vertical plane of the telescope, in measuring horizontal angles, is controlled 

 by the front plate level or by the striding level, which are not affected by this deficiency in the weight of the 

 counterpoise, and inasmuch as vertical angles are controlled by the Level attached to the vertical circle, i twas 

 deemed best, not to add unnecessarily to the weight of the instrument. A true equipoise of the instrument 

 can be obtained, however, by simply lengthening out the milled headed screws by which the counterpoises are 

 secured to the instrument. 



As a rule for the more ordinary purposes the plate levels alone can be depended on, but for very close 

 work in running l ; nes down or up a deep shaft, etc., or when horizontal angles must be measured with the 

 telescope in the excentric bearings, the striding level should be depenaed on only, and then, in order to elimi- 

 nate all errors of collimation and inequality, if any, in the pivots of the horizontal axis of revolution, the tele- 

 scope should also be reversed over its bearings. The telescope can be reversed through the standards in both 

 bearings, or it may be reversed over the bearings, as the case may be. Ordinarily, when in the normal bearings, 

 it should be reversed only through the standards as being more convenient and more accurate. 



Both, the normal and the excentric wye adjustment of the telescope should be made with the striding 

 level alone. The latter being very sensitive (r div. of level=io"of arc), there need be no uneasiness on 

 the part of the engineer should the adjustment under ordinary circumstances be not completed within one or 

 two divisions of its graduated tube, but, of course, as the sights are longer and approach a vertical line, it is of 

 great importance to pay the strictest attention to the adjustments of the striding level and wye bearings of the 

 telescope. 



To lift the telescope out of its bearings, the spring bolts situated on top of the protection clasps must first 

 be withdrawn, when the latter can be turned aside. Next withdraw about one-tenth inch the spring bolt of 

 the telescope's clamp and also that of the vernier frame's tangent screw by means of the milled headed nut at 

 the end of each spring box. Now lift the telescope out of its bearings and either reverse over the bearings or 

 insert it in the excentric bearings, as the case may be, and again release to the fullest extent the spring bolts of 

 the tangent screws under operation. This being accomplished, all settings of the telescope in the vertical 

 plane must be made by its clamp and tangent screw alone, and no attention need be paid to the clamp of the 

 vernier frame. It is only when vertical angles must be measured that the bubble of the level situated on the 

 vernier frame must be brought to the center of the tube by means of its tangent screw. Good results for verti- 

 cal angles may be obtained with this instrument, although the plates may not be leveled up accurately, if due 

 regard is paid only to the fact that the bubble of this level must be placed in the center of its tube before a 

 reading can be made. 



To make the adjustment of this level proceed thus : Place the telescope in the horizontal plane by 

 means of its tangent screw, then move the vernier frames' tangent screw until the zero line of the double 

 verniers, marked A, is in coincidence with the zero line of the vertical circle, and now raise or lower the adjusting 

 screw of this level, as the case may be, until the bubble is in the center of its tube. 



It is now supposed that the zero line of the double opposite verniers, marked B, are also in coincidence 

 with that of the vertical circle. If not, the verniers marked B can be moved after releasing the capstan- 

 headed screws, until both zero lines on that side of the vertical circle are also in coincidence. However, this 

 is a very laborious proceeding for Fthose uninitiated in this work, and as it cannot always be made quite 

 exact, owing to the mode of mounting the telescope on its axis, it will be found easiest to eliminate errors of 

 excentricity in the graduation of the vertical circle and verniers by reversing the telescope and taking the mean 

 of the readings. The vertical circle is graduated from o to 90? and back, and the verniers are double, so that 

 angles of elevation and depression can be read with ease and dispatch. For further information see page 147. 



