Tables and Formulae Useful in Surveying, Geodesy, and Practical Astronomy: Including Elements for the Projection of Maps, and Instructions for Field Magnetic ObservationsU.S. Government Printing Office, 1873 - 310 pages |
Common terms and phrases
&c.—Continued altitude angle Arcs-Values of Dm AWHO AWHO axis azimuth Barometer chord chronographs chronometer circumpolar star collimation column Computation corresponding cos² cubic cubic centimetre culmination D₁ declination deflection Degrees of Fahrenheit determined diff Differences of Latitude Distance dm dp dm Dm in Yards dp dm dp elongation English inches Fahrenheit Feet formula horizontal hour-angle humidity instrument Intermediate minutes interval Latitude length limb log H Longitude LXIII.-Longitude by Lunar LXVI.-Field Magnetic Observations mean noon mean solar measured meridian Meridional Arcs-Values metre middle wire miles oscillation parallax parallel Peirce's Criterion plane Polaris Polyconic Projection-Co-ordinates probable error reduced refraction right ascension sextant sidereal sin² Square root stations TABLE tangent telescope temperature thermometer tion toise transit w w w w w 30 XXIV.-Squares and Square zenith-distance ΙΟ ΙΟΙ ΟΙΟ обо ळे
Popular passages
Page 16 - That the tables in the schedule hereto annexed shall be recognized in the construction of contracts and in all legal proceedings as establishing in terms of the weights and measures now in use in the United States the equivalents of the weights and measures expressed therein in terms of the metric system...
Page 288 - ... is disregarded, and the true value is — Such is the simple and obvious application of the telegraph to the determination of longitudes; but the degree of accuracy of the result depends greatly — more than at first appears — upon the manner in which the signals are communicated and received. Suppose the observer at A taps upon a...
Page 99 - Schmidt's computation would make it 443.29977 lines, and both numbers are confirmed by Airy's results. The legal metre is thus, in fact, as Dove remarks, a legalized part of the toise du Perou, and this last remains the primitive standard. But it must be added that a natural standard, in the absolute sense of the word, is a Utopian one, which ever-changing Nature never will give us. The metre is, for all practical purposes, what it was intended to be, a natural standard ; though it must be confessed...
Page 114 - They are based on a polyconic development of the earth's surface which supposes each parallel of latitude represented on a plane by the development of a cone having the parallel for its base, and its vertex in the point where a tangent to the parallel intersects the earth's axis. The degrees on the parallel preserve their true length and the general distortion of area is less than in any other mode of representing a given portion of the earth's surface.
Page 102 - In terms of the coordinates of rectangular axes referred to one of the points of the triangulation, the latitude and longitude of which are known, — y being the ordinate in the direction of the meridian, and x the ordinate perpendicular to it, — the...
Page 288 - It is evident that the clocks at two stations, A and B, may be compared by means of signals communicated through an electrotelegraphic wire which connects the stations. Suppose at a time T by the clock at A, a signal is made which is perceived at B at the time T' by the clock at that station.
Page 12 - The standard avoirdupois pound of the United States, as determined by Mr. Hassler, is the weight of 27.7015 cubic inches of distilled water. By this weight are weighed all coarse articles, such as hay, grain, chandlers' wares, and all the metals, except gold and silver.
Page 193 - ... sundial. Mean solar time is derived from the time employed by the earth in revolving on its axis, as compared with the sun, supposed to move at a mean rate in its orbit, and to make 365.242218 revolutions in a mean Gregorian year. It...
Page 196 - A pedestal and having a triangular plate of metal, Fig. 1, called the gnomon, rising from its center and inclined toward the meridian line of the dial at an angle equal to the latitude of the place where the dial is to be used. The shadow of the edge of the triangular plate moves around the northern part of the dial from morning to afternoon, and thus supplies a rough measurement of the hour of the day. The style or gnomon, as it always equals the latitude of the place, can be laid out as follows...
Page 11 - The gallon is a vessel containing 58372.2 grains, (8.3389 pounds avoirdupois,) of the standard pound of distilled water, at the temperature of maximum density of water, the vessel being weighed in air in which the Barometer is 30 inches at 62° Fahrenheit.