Treatise on Mathematical Instruments: Their Construction, Adjustment, Testing and Use Concisely ExplainedVirtue Bros. & Company, 1866 - 185 pages |
From inside the book
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Page 10
... intersect , is the same as this distance measured upon the highest or lowest of these lines , that is , as one of the subdivisions before mentioned : but the distance beween the perpendicular , which passes through the zero point , and ...
... intersect , is the same as this distance measured upon the highest or lowest of these lines , that is , as one of the subdivisions before mentioned : but the distance beween the perpendicular , which passes through the zero point , and ...
Page 15
... intersections of these lines with the quadrant c B draw right lines parallel to the radius o c , to meet the radius o B , and we shall have a scale of latitudest . Corresponding lines of hours and latitudes may also be con structed ( as ...
... intersections of these lines with the quadrant c B draw right lines parallel to the radius o c , to meet the radius o B , and we shall have a scale of latitudest . Corresponding lines of hours and latitudes may also be con structed ( as ...
Page 16
... intersect B c in c , and join a c . 2nd . To measure the angle contained by the straight lines A B and A c already laid down . Open the compasses to the ex- tent of 60 ° on the line of chords , as before , and with this ra- dius ...
... intersect B c in c , and join a c . 2nd . To measure the angle contained by the straight lines A B and A c already laid down . Open the compasses to the ex- tent of 60 ° on the line of chords , as before , and with this ra- dius ...
Page 17
... intersection of its given meridian and parallel of latitude . The plane upon which the circles are to be delineated is called the primitive , and the circumference of a circle , de- scribed with a radius , representing , upon the ...
... intersection of its given meridian and parallel of latitude . The plane upon which the circles are to be delineated is called the primitive , and the circumference of a circle , de- scribed with a radius , representing , upon the ...
Page 24
... Intersect them at right angles by another line , ef , called the six o'clock line . From the scale of latitudes take the latitude of the place with the compasses , and set that extent from c to e and from a to ƒ on the six o'clock line ...
... Intersect them at right angles by another line , ef , called the six o'clock line . From the scale of latitudes take the latitude of the place with the compasses , and set that extent from c to e and from a to ƒ on the six o'clock line ...
Common terms and phrases
accuracy achromatic adjustment altitude axis azimuth beam compasses bisected breadth bubble called chromatic dispersion clamp coincide colatitude compasses construction correct cross wires described diaphragm distinct vision Ditto ditto divided drawing edge equal error extent will reach eye-piece feet figure fixed focal length given number goniometer graduated half horizontal inches index glass instru instrument intersection IVY LANE latitude lens lenses limb line of collimation line of numbers line of sines logarithmic means measured ment meridian microscope number of degrees object-glass observed paper parallax perpendicular placed plane position primary divisions prism protractor quarter girt radius rays reading reflected image reflector refracting refracting telescopes represent right angles right ascension round secants sector sextant side Slide Rule sliding speculum spherical aberration spirit level square staff station subdivisions tangents telescope theodolite transit transverse distance triangle tube turning vernier scale vertical circle zero
Popular passages
Page 5 - To which is added, a description of the Principles and Practice of Isometrical Projection. By JF HEATHER, MA -With 14 Plates.
Page 69 - ... that the sine of the angle of refraction bears a constant ratio to the sine of the angle of incidence...
Page 98 - ... of this field of view. We must therefore place some fixed point in the field, of view, and in the focus of the eye-piece, and the point to which the measurement will have reference will be that point of the object viewed, which...
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Page 143 - ... of them, those which apply to the eye-end of the telescope will answer much better ; the former having their errors magnified by the power of the telescope, will, in proportion to this power, and those errors, be less distinct than the latter. " In taking distances, when the position does not vary from the vertical above thirty or forty degrees, the handles which are attached to the circle are generally most conveniently used ; but in those which incline more to the horizontal, that handle which...
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