Show J the shattuck potent solar attachment 11 I 1 lei lei lei calm M ainsworth sons of denver W f I 1 0 colo have placed upon the market a new and improved solar attachment designed and patented by orville F shattuck a prominent mining engineer of that city the attachment is arranged to fit over the objective end of the telescope in place of the cap which renders t easily detachable and makes it unnecessary to send a transit to the factory to have it fitted provisions being K PIG FIG I 1 N I 1 made whereby an engineer enc can give the ac i curate dimensions required and place his 1 i order when in the field thus affecting a sav ing in trans transportation ort atlon charges and time i i this solar attachment overcomes by its t t optical construction the polar adjustments so difficult to maintain in others being 1 dent only on the accuracy of the vertical are arc and limb the two most carefully constructed parts of the transit hence giving results com with the accuracy of the inspru ment to which it is attached it equals direct observation for accuracy and can be operated oper ared in one ode tenth the time fig 1 shows the attachment three fourths of its actual size for instruments having no vertical are arc a latitude level is provided at small expense 1 and is even more accurate than the are arc the difficulties attendant upon the use of former solar attachments their inaccuracies ewhen E when not in perfect adjustment the difficulty C s jl 4 1 Is FIG 2 C of maintaining their adjustments and their of unprotected position on the transit have f rightly prejudiced engineers against them f the reliability of the sol solar ar attachment own herewith h depends upon principles similar to those of the sextant i e that a ray of light which suffers reflection twice in the same place is bent at an angle with its original direction equal to twice the angle between the two reflecting surfaces referring to fig fia 2 which is a sectional view in the plane of the attachment about three fourths actual size the main frame AA carries the stationary mirror H and revolves axially by means of a bearing in the cap B which fits over the objective end of the transit C is a clamp ring used in connection with the clamp and tangent screw not shown for rotating the frame AA about its axis axis the movable mirror I 1 is adjustable to any re required angle being mounted on a swinging arm D which is provided with an adjusting screw E a graduated differential nut P and a clamp G the ray of light enters from above as indicated by the arrow and is incident upon the movable mirror I 1 it is thence reflected to the stationary mirror H thence in ahr through buah the object glass to the cross wires of the instrument thus the maintenance of the angle between the incident and emergent ray depends upon the angle between the mirrors rather than upon the polar bearing the declination angle corrected for refraction is set off by means of the movable mirror e A FIG 3 actuated by the screw E and the differential nut F the method being to sight at some object on the horizon B fig 3 with the solar attachment off the telescope level and the vernier set at zero then with the lower plate clamped and the vernier set at the south polar distance corrected for refraction which has been previously computed sight at the same object B fig 3 with the solar attachment in place bringing the object onto the cross wires by means of the adjusting screw E and the differential nut F then referring to fig 3 angle ODE equals angle CAB if the object sighted be less than five or six thousand feet distant allowance is made for parr allax by making the distance BB equal to the distance from the axis of the telescope A to the optical center or the solar attachment now depress the telescope to the latitude of the place of observation see figs 4 and 5 revolve the solar about its axis and the tran sit in a horizontal plane until the image of the sun is brought to the proper roper posit position iop on the cross wires the line of then ihen becomes the polar axis with the transit in the meridian and the solar revolved about its axis will follow the path of the sun the engineer having baving carefully set off his angles and knowing that his transit is in adjustment is assured of reliable results fig 4 shows an operator making an observation to determine the meridian fie fi 5 is a graphic illustration of the same when the suns declination is north 11 degrees 26 min ANEW 2 71 1 0 N jk FIG 4 utes A being the axis of the telescope and PP the polar axis coincident with the line of after the transit has been set in the meridian the read reading in a of the differential nut is taken and the attachment att a cament is removed it weighs less than three ounces and may be carried in the pocket without fear of damage in taking subsequent observations during the day as a check on the work it is only necessary to set off the hourly e hange change in declination cli nation by means of the graduated differential diff er nut dut each division of which represents one minute of arc place the attachment in position and if the instrument be in the meridian the sun will come to the proper position on the cross wires another valuable feature of this solar attachment tach ment is its adaptability to underground surveying in connection with the delicate level under the transit telescope it is espee FIG 5 ally useful in carrying accurate traverse lines up or down shafts or steep inclines in the same manner as with side gide and top telescope Oata catalogue logue C 6 giving complete description will vill be mailed on request by wm win ainsworth fc sons honsl sole sol manufacturers |