A Collection of Tables and Formulæ Useful in Surveying, Geodesy and Practical Astronomy, Including Elements for the Projection of Maps

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Taylor & Maury, 1853 - Astronomy - 242 pages
 

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Page xxi - The units of capacity measure are the gallon for liquid, and the bushel for dry measure. 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 82° Fahrenheit, The.
Page 13 - Aroirdupois. 1 myriagramme = 22-0485 Ibs. Avoirdupois. 1 quintal = 1 cwt. 3 qrs. 25 Ibs. The unit of superficial measure is "the are, a surface of ten metres each way, or 100 square metres. The unit of measures of capacity is the litre, a vessel containing the cube of a tenth part of the metre, and equivalent, to 0-220097 parts of the British imperial gallon. The standard temperature is 32° F. All the divisions and multiples of the units are decimal.
Page 29 - Multiply the double meridian distance of each course by its northing or southing. 2. Place all the plus products in one column, and all the minus products in another. 3. Add up each column separately and take their difference. This difference will be double the area of the land. In balancing the work, the error for each particular course is found by the proportion : as the sum of the courses is to the error of latitude, (or departure,) so is each particular course to its correction.
Page 10 - Gallon., containing Ten Pounds Avoirdupois Weight of distilled Water weighed in Air, at the Temperature of Sixty two Degrees of Fahrenheit's Thermometer, the Barometer being at...
Page 140 - Greenwich mean time, and is continued through the 24 hours, to the following mean noon, when another day begins. It may therefore be called the mean astronomical day, although, in practice, astronomers begin the day at the moment the true Sun's centre is on their meridian. In the civil, or common, method of reckoning, the day is supposed to commence at the preceding midnight...
Page 21 - The area of each end added to four times the middle area, and the sum multiplied by the length divided by 6, will give the solid content. If the measures used in the calculation are yards, the result will be the content in cubic yards ; but if they are feet, the result must be divided by 27, to obtain the corresponding number of yards. CALCULATION OF THE TRIANGULAR PORTION O.
Page 63 - 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 129 - ... from its centre perpendicular to its direction : the experiments of vibration consist in suspending the magnet which was used as the deflecting magnet in the experiments of deflection, and observing its time of vibration. By the first part of the process (or the experiments of deflection) we obtain the ratio of the magnetic moment of the deflecting magnet to the Earth's horizontal magnetic force at the place of observation ; the latter being to the former as 1 to the sine of the angle of deflection...
Page 29 - The double meridian distance of any course is equal to the double meridian distance of the preceding course, plus its departure, plus the departure of the course itself.
Page 157 - T = (V — t ) = the interval of time between the observations, expressed in hours and decimals. L = the latitude of the place of observation : (minus when south.) D = the...

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