172 



C. L. Berger & Sons' Universal Mining Transit with Duplex 

 Telescope Bearings, 



This instrument, represented by tin- annexed cut,-, was designed by us Juno 10, 

 1889, in response to an urgent demand upon us to construct an Instrument which 

 could be depended upon to give the Closest results under the nio-t Irving ein-um- 

 stances. It was designed to do accurate work in measuring horizontal angles 

 between points, one of wliieli maybe depressed as much as eighty or ninety drives 

 below the hori/.on, while the other maybe as much elevated above, the horizon; and 

 also to measure with equal accuracy angles of elevation or depression above oT 

 belo\v the horizon. It was planned to meet the requirements of the Mining Engi- 

 neer, who must have the exact location of every shaft and tunnel in a mine, th-- 

 length of which may aggregate a number of miles, and necessarily the insi rument. 

 must be so constructed, that it may be portable, as light in weight as consist .'-nt, 

 with the end to be accomplished, adjustable by the engineer at the bottom of a 

 mine, and its delicate parts so protected from the dripping of water from roof of 

 tunnel or from the shafts, that they may not be injured. The in-1 rnmenf having 

 but one telescope, is as simple in construction as one with a universal adaptation 

 can be made. It is necessarily a little crowded in order to be as strong, as com- 

 pact, and as light as possible. To produce the last result, lightness, not only the 

 frame of the standards, the vertical circle, its verniers and vender frame, etc., but 

 also all the detached parts are made of aluminum (see article "Aluminum for Insi ru- 

 ments of Precision," page 27). No attempt at elaborate finish of the exterior sur- 

 faces of these parts has been made, as it would require a different design at the 

 expense of simplicity, lightness, strength and general efficiency. For the most 

 part the} T are treated with our cloth finish, or they will be bronzed in black or green. 

 The form of standard is of a unique design : two arms reach out from its bas. 

 from the usual bearings, and offer an excentric bearing for the support of the tele- 

 scope when it may become necessary for the engineer to direct the line of sight. 

 down or up a shaft, thus affording two bearings for the horizontal axis of revolution. 

 One of these may be called the normal, the other the excentric bearings. To accom- 

 plish the best results in stiffness and solidity these standards are cast in one piece. 

 There are protection clasps over the bearings of both the normal and excentric stand- 

 ard. Those over the excentric bearings may be omitted if so desired. A counterpoise 

 is to be used when the telescope is in the excentric bearings. The striding level 

 furnished with this instrument is of a most sensitive character. In cases, however, 

 where this instrument is intended for ordinary good work only, such as could be ac- 

 complished with Mining Transits Nos. 5 or 6 when provided with a side telescope, 

 a striding level as described on page 56, resting on special collars between the 

 standards, can be supplied. 



In order to afford increased steadiness, the extension tripod furnished with this 

 instrument is larger than usual for its size, and the vertical centers are of the 

 same length and diameter as those in our transits No. 1. The lamp targets (if any 

 are ordered) are of the pattern shown in the cut. They are interchangeable with 

 the transit on the tripods. The telescope should be inverting for best results. 



Weight of instrument, standard frame of aluminum, about n Ibs. 



counterpoises ..... 4 " 



compass, frame of aluminum, i\ " 



striding level, " it u ^ 



one lamp target 4 " 



one tripod about 12 Ibs.; two tripods ' 24 " 



mahogany box, containing instrument and its attachments, etc., . about 30 Ibs. 



one lamp target and one plumb 

 Gross weight of instrument, complete, packed securely for shipment in three boxes ' 100 " 



No. 8. Universal Mining Transit,as in cuts. Horizontal and vertical circles, 

 5 inches; graduations on solid silver, double opposite verniers reading to minutes, 

 etc. ; 5-inch level to telescope ; 3-inch level to vertical circle ; 5-inch striding level ; 

 two plate levels. Telescope 9 inches, aperture 1 inches if erecting, and 1^ inches if 

 inverting; power 18 diameters; fixed stadia wires; illuminator shade; prism. Mag- 

 netic needle 3J inches. One lamp target, packed in separate box. Two extension 

 tripods, two plumb bobs, etc. price> completc as above , $ 6 *O.OO 



Price of this instrument, without lamp target, tripod, and plumb-bob, $90.00 lass. 



detachable compass, . . . 40.00 " 

 " protection clasps to excentric bearings, 10.00 ' 

 " " with striding level resting on special collars between 



the standards, see page 148, 



No. 8a. Universal Mining Transit as in No. 8, but with 2 lamp 

 targets (packed in one box), 3 extension tripods, and 3 plumb bobs. Price $71O.O< ' 



