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 3
... draw arcs or circles with ink or black lead , compasses with a moveable point are used . In the best description of these compasses the end of the shank is formed into a strong spring , which holds firmly the moveable point , or a pen ...
... draw arcs or circles with ink or black lead , compasses with a moveable point are used . In the best description of these compasses the end of the shank is formed into a strong spring , which holds firmly the moveable point , or a pen ...
Page 7
... draw lines of any required fineness or thick- ness . One of the blades is framed with a joint , so that by taking out ... drawn , and care should be taken that both points touch the paper ; and the observations equally apply to the pen ...
... draw lines of any required fineness or thick- ness . One of the blades is framed with a joint , so that by taking out ... drawn , and care should be taken that both points touch the paper ; and the observations equally apply to the pen ...
Page 8
... draw a straight line between two points upon a plane , we lay a rule so that the straight edge thereof may just pass by the two points ; then moving a fine - pointed needle , or drawing - pen , along this edge , we draw a line from one ...
... draw a straight line between two points upon a plane , we lay a rule so that the straight edge thereof may just pass by the two points ; then moving a fine - pointed needle , or drawing - pen , along this edge , we draw a line from one ...
Page 10
... Draw eleven parallel equidistant lines ; divide the upper of these lines into equal parts of the intended length of the primary divisions ; and through each of these di- visions draw perpendicular lines , cutting all the eleven ...
... Draw eleven parallel equidistant lines ; divide the upper of these lines into equal parts of the intended length of the primary divisions ; and through each of these di- visions draw perpendicular lines , cutting all the eleven ...
Page 13
... draw the diagonals with accuracy , and we have no check upon its errors ; while in the former the uniform manner in which the strokes of one scale separate from those of the other is some evidence of the truth of both * . * In Mr ...
... draw the diagonals with accuracy , and we have no check upon its errors ; while in the former the uniform manner in which the strokes of one scale separate from those of the other is some evidence of the truth of both * . * In Mr ...
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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