166 

 .22 Complete Mining Transit No. 6D, without Compass. 



Shown with our Patent Interchangeable Auxiliary Telescope, Style I. 



fi .** (See pages 106 and 107.) 



6 - Responding to many solicitations to make for mines containing magnetic ore, 

 j^3 or an electric plant, a transit similar in style and accuracy to our No. 11 'seepage, 



180), we have designed the instrument illustrated on opposite page. It is lii/ht, 

 portable, and of the same size en our Nos. 4, and C> traim,tH ; lint, owing to the 

 omission of the compass, the standards are cast in a single piece, affording gre.it er 

 lateral stiffness, with increased capability to withstand rough treatment. It is 

 adapted to all the complex conditions prevailing in underground work, and is very 

 simple in style and manipulation. It possesses all the advantages, as regards 

 accuracy of division, highest permissible telescopic power, and sensitive spirit- 

 levels of larger instruments. With the interchangeable auxiliary telescope added 

 for use in steep sighting, either on top or on the side of the main telescope, as 

 required, it becomes a most capable instrument for correctly solving what would 

 otherwise require special instruments and methods. When the auxiliary telescope 

 is detached, it is just as applicable to the common work in the mine or on tin; 

 surface as our regular engineers' and mining transits N OS. 4, 2 and <>. 



02 The T-tihaped standard frame of the telescope is made of aluminum, covered with a fine dartc Japan 



not affected by moisture ; all other parts are finished in the same manner as in our other instruments. The 

 plate-levels * are of our standard character and length, mounted directly upon the upper plate, where they 

 are easily accessible for the purpose of adjustment and ready observation, and are fully protected from falling 

 bodies. The principal plate-level is directly under the eye-end of the telescope. The two opposite verniers 

 of the horizontal circle are in line of sight with the telescope, and are protected from dripping water by ce- 

 mented glass covers. The circle itself is provided with two rows of figures from o to 360, in opposite direc- 



^ tions, with double verniers to correspond to them (unless otherwise ordered). The vertical circle, with figures 



from o to 180, both ways from zero, has a double vernier, to enable the observer to read angles of elevation 



.25 01 or depression with equal facility, and is provided with an aluminum protection guard, which carries the ver- 



~ nier and also serves to readily adjust the latter to zero. Double opposite verniers can also be placed on the 



vertical circle, when the figures will run from o to 90 each way and back to zero. The transit has inverting 

 telescopes (unless otherwise ordered). A new and important feature of the instrument, which greatly increases 

 its value, is this: t ; ie line of collimation of the main telescope is adjusted for distant, very near, and interme- 

 diate distances, by means of our recently patented device, to a nicety never before attained; and no readjust- 

 ment for near distances is necessary except after a severe accident. 



The interchangeable auxiliary telescope, described on pages 106 and 107, is fur- 

 nished in two styles. 



Style I, illustrated on opposite page, has no trivet, and is therefore non-adjust- 

 able, but it has been so much improved that the line of collimation of its principal 

 wire, which is the vertical one when used as top telescope, and becomes t he hoi i- 

 zontal wire when used as a side telescope, lies so nearly parallel to that of the 

 ^ if t Z main telescope as to be practically correct in most cases. 



S.5.S ? Style II, with the trivets, can be adjusted so that the line of collimation of both 

 ~ 8 S 5 of its wires will be truly parallel to those of the main telescope. All of the chief 

 H ~ 5 features of this transit are protected by letters patent issued to us. 



_ O JJ Weight of Mining Transit No. 6D n Ibs. 



_ -- f ~ auxiliary telescope and counterpoise, each 12 oz 'i " 



T3 *> L ' ~ ; extension tripod about 9 



.2 instrument in mahogany box, with plumb-bob, sun-shade, reading-glass, etc., etc. " 22 



T 1 ' "E '"\. r Gross weight of instrument complete, packed securely for shipment in 2 boxes . 50 



No. 6D. Mining Transit without Compass, as in cut, with styi.- i in- 



5 .5 'I > terchangeahle Auxiliary Telescope. Horizontal and vertical circles, 5 i nclies; solid silver 



?T~2 graduations reading to minutes; ground glass shades ; 5-inch level to telescope; 



., 2 . - 2 plate-levels; inverting telescope, 9| inches long by H-inch aperture; if erecting. 



P 9 9 a by H inches) ; powers, 20 diameters; inverting auxiliary telescope, r.A by 1 inch 



X".2~ aperture; (if erecting, 7 by }<* inch); fixed stadia wires; gradienter; ! illuini- 



S^'o r nator shades; extension tripod, etc. Price, complete as above, $335.OO 



^^^'^ Price, with double opposite verniers to vertical circle, rxfra, S " 



o a, JJH E. " " prism attach in en t to eye-piece 



'S-:z'~? " " quick-leveling attachment 



_ V. 7 \ " " style II. auxiliary telescope in place of style I. 



7 - | //-///^r// style 1. auxiliary telescope l'>s, 

 z I r 7 " with one illuminator shade only for main telescope 



c; s x M 



j i . 7 * To P lace these levels below the upper plate and within the space formed by it and tlu- graduated 



f ~- as is the practice in some instruments of minor grade and in some Surveyors' compasses, li.is tl, 



i X-x'i- vantage of partly obscuring them from view, and that such levels are too small In diameter and length to M 

 * 2 reliable and are apt to loose tlu-ir adjustment, and that they cannot be reached in case of required tn 



= v But the most serious objections are that the two large openings required in the upper plate of a transit i 



a full view, weaken the latter to ruch an extent as to jeopardize thf stability of the superstructure upon which 

 the permanency of the adjustments depends in case of rough treatment. 



^^ Our Iiit-r-lianj;-:ill :i uxiliary t l^rop-, Ix-iny: >t <li- nu-t -n l>-1 :int ial -.n*t i -n I im 



ami < h.ii ;u I<T, may also ! used for fimlin- meridian ami Latitude \\lx-n 

 ol-.cr\ at ion^ cannot ! maoc \vrtli tin- main I !.< <>p " pa^i- I OS. 



