164 



The Berger Solar Attachment an<l Top Telescope 



Combined. 



Attachable to Transits. Si/.cs I. '2 ami :!. hat in:; :i I nil Vt-rtical < irclc. 

 For 1. S. Deputy rarveyon, Suru-yors ami Mining Knir inccrx. 



This Solar Attachment and Top TeL-scopr combined may he used either as a ih-st 



Cla88 BOlar in Surface Surveying for determining meridian. OF as a Mrst class auxiliary 



top telescope in underground work when objects cannot he seen with the main tele- 

 scope. The solar telescope being longer and more powerful tlian heretofore, permit- 

 it t be also used for mine work, and as i!s horizontal axis is provided with our 

 patented lateral adjustment * (see cuts <i. ,i on right-hand si<le of illust ration >, \ve are 

 enabled to place its line of collimation so truly al>ove that of the main telescope a> to 

 be exactly in the same vertical plane, and therefore this auxiliary telescope can be, 

 depended upon to the same extent as those of our regular Mining Transits. 



As a solar attachment, or meridian Under, it is in principle like Pearsons' and that 

 formerly made by us (see cut page f7). not requiring computation ; but instead of the 

 lens bar. or small telescope,! it is now constructed with a telescope of one-inch aperture 

 and Six-inch focal length, provided with a diagonal eye-piece, colored glass and wires 

 arranged in a square, as shown on next page and described on pages iia. and HH. 



This solar attachment fastens by means of a screw to the cross axis of the transit 

 telescope. It has no declination arc. The declination of the son and the co-latitude 

 of the place of observation. are both set off by the vertical circle of the transit. All 

 settings for position, viz. that of the polar axis, to be truly at right angles to line of 

 sight of main telescope and the setting of the declination, are seen red by the spirit 

 l-vel attached to the solar telescope. The degree of precision and simplicity of manipu- 

 lation attained thereby is commensurate with that of our Engineers' Transit. 



To determine true meridian at any hour of the day it is only necessary that the 

 declination and refraction of the sun on that particular day and hour be known to the 

 observer, and that the polar axis be raised precisely to the co-latitude of the place of 

 observation. The adjustments are few and simple, and need to be verified only from 

 time to time ; besides, they can be readily verified, being similar to those in the transit 

 proper. 



Latitude and transit observations can also be made with this auxiliary telescope 

 when the sun's altitude is too high for observations with the main telescope, in tin- 

 same manner as described on page 108 for our Interchangeable Auxiliary Telescope 

 style I. 



This solar attachment and top telescope combined can be readily attached or de- 

 tached from the transit without altering its adjustments. When detached the t ran.- it 

 is then simply an ordinary complete Engineers' and Surveyors' Transit. 



By the use of our Latitude Level \ (fastening to the cross axis at the side of the 

 vertical circle, see cut) not requiring a reading of the vertical circle for every setting 

 of the polar axis for latitude except once in a day, observations can be, made repeatedly 

 with speed and accuracy. Indeed, with the declination and refraction of the sun pre- 

 viously worked out for the various hours of the day, observations can be made nearly 

 as fast as a needle of the surveyor's compass can be read. A concise description and 

 use of both attachments will be found in the Manual. 



The weight of the solar attachment and top telescope combined is 1 lb.. with coun- 

 Code Words: ter I K)ise ' 2 11)S ' : tll:lt ^ tlie ^ atitu(le level about y lb. IJoth are screwed into the in- 



strument box. 



i>atura Price of Solar Attachment and Top Telescope Combined, 



as above, complete with counterpoise, prism and colored glass, . . $<>S.OO 

 Price of Solar Attachment with Small Telescope, noii- 

 adjustable laterally as generally supplied for solar work alone, and 

 without counterpoise,;? bu' with prism and colored -lass, . . . $,~>O.OO 

 Price of Latitude Level, as in cut, . $15.OO 



* Other telescopic solars of similar design as heretofore made may be out from l /s to #" from th> 

 ter of the main telescope, and then of course there must be a divergence of the lines of si^lu <>t both tele*COpefl 

 involving errors to that amount. 



t The honor of first conceiving the ide.i of applying n small telescope in plan- i.f the 1ms Kir and <>f 

 a spirit level for the accurate setting of the polar axis, belongs to Mr. ('. K. I'.erger, <>t this firm. > 

 logue of 1878. 



% This latitude level can also be used for grades and distance measurements, etc. It will he found to form 

 a very useful adjunct to the Engineers' Transit, even with nit the solar atta< -hment. 



It is not strictly necessary to counterpoise the smaller solar attachment in order to obtain good work. 



