scholarly journals XXV. On the application of the pendulum to the determination of the mean density of the earth

1885 ◽  
Vol 19 (118) ◽  
pp. 219-222
Author(s):  
J. Wilsing
Keyword(s):  
The Earth ◽  
The Mean

scholarly journals XIV. On a determination of the mean density of the Earth and the gravitation constant by means of the common balance

1891 ◽  
Vol 182 ◽  
pp. 565-656 ◽  
Keyword(s):  
Royal Society ◽  
Torsion Balance ◽  
Chemical Balance ◽  
The Earth ◽  
The Common ◽  
The Mean ◽  
Common Balance

In a paper printed in the Proceedings of the Royal Society,' No. 190, 1878 (vol. 28, pp. 2-35), I gave an account of some experiments undertaken in order to test the possibility of using the Common Balance in place of the Torsion Balance in the Cavendish Experiment. The success obtained seemed to justify the intention expressed in that paper to continue the work, using a large bullion balance, instead of the chemical balance with which the preliminary experiments were made. As I have had the honour to obtain grants from the Royal Society for the construction of the necessary apparatus, I have been able to carry out the experiment on the larger scale which appeared likely to render the method more satisfactory, and this paper contains an account of the results obtained.

scholarly journals III. Account of the observations and computations made for the purpose of ascertaining the amount of the deflection of the plumb-line at Arthur’s seat, and the mean specific gravity of the Earth; with an account of the observed and computed amount of the local attraction at Arthur’s seat and at the Royal Observatory at Edinburgh

1857 ◽  
Vol 8 ◽  
pp. 45-47
Keyword(s):  
Plumb Line ◽  
Great Pleasure ◽  
Ordnance Survey ◽  
The Public ◽  
The United Kingdom ◽  
The Earth ◽  
Royal Observatory ◽  
The Press ◽  
The Mean

Col. James begins by observing, that as the Royal Society has, from the very commencement of the Ordnance Survey of the United Kingdom, taken a deep interest in its progress, he has great pleasure in announcing to the Society that all the computations connected with the Primary Triangulation, the measurement of the Arcs of Meridians and the determination of the figure and dimensions of the earth are now completed, and that the account of all the operations and calculations which have been undertaken and executed is now in the press, and will shortly be in the hands of the public. In the progress of these operations it has been found, on determining the most probable spheroid from all the astronomical and geodetic amplitudes in Great Britain, that the plumb-line is considerably deflected at several of the principal Trigonometrical Stations, and at almost every station the cause of the deflection is apparent in the configuration of the surrounding country.

scholarly journals An experiment with the balance to find if change of temperature has any effect upon weight

1905 ◽  
Vol 76 (512) ◽  
pp. 445-457 ◽  
Keyword(s):  
Low Temperatures ◽  
Secondary Effect ◽  
Boiling Liquid ◽  
The Earth ◽  
Exact Determination ◽  
The Mean ◽  
Very High ◽  
The Ideal

In all the experiments hitherto made to determine the gravitative attraction between two masses, the temperature has not varied more than a few degrees, and there are no results which would enable us to detect with certainty any dependence of attraction upon temperature even if such dependence exists. It is true, as Professor Hicks has pointed out, that Baily’s results for the Mean Density of the Earth, if arranged in the order of the temperature of the apparatus when they were obtained, show a fall in value as the temperature rises. But this is almost certainly some secondary effect, due to errors in the measurements of the apparatus, or to the seasons at which different attracted masses were used. The ideal experiment to find if temperature has an effect on gravitation would consist in one determination of the gravitative attraction between two masses at, say 15°C., and another determination at, say, the temperature of boiling liquid air. But the difficulties of exact determination at ordinary temperatures are not yet overcome, and at any very high or very low temperatures, they would be so much increased that the research seems at present hopeless.

scholarly journals IV. India’s contribution to geodesy

1895 ◽  
Vol 58 (347-352) ◽  
pp. 157-159
Keyword(s):  
The Earth ◽  
Figure Of The Earth ◽  
The Mean

This paper gives a summary of the operations which have been completed up to date in India to furnish the necessary data of the lengths and the amplitudes of meridional and longitudinal arcs for a mathematical determination of the mean figure of the earth. It shows that geodetic investigation has already greatly influenced the operations of the Great Trigonometrical Survey of India, from its very commencement at the beginning of the present century. It describes the principal triangulation which has been laid out over the whole face of the country, mostly in meridional and longitudinal chains, and shows how it has been finally reduced and made consistent throughout by processes of calculation which are fully set forth in the published accounts of the operations.

Bouguer Redeemed: The Successful 1737-1740 Gravity Experiments on Pichincha and Chimborazo

2010 ◽  
Vol 29 (1) ◽  
pp. 1-25 ◽  
Author(s):  
John Smallwood
Keyword(s):  
Plumb Line ◽  
Near Surface ◽  
The Earth ◽  
Digital Elevation ◽  
The Mean ◽  
Good Determination ◽  
Elevation Model ◽  
Academy Of Sciences ◽  
Regional Gravity

During the 1735-1745 French Academy of Sciences expedition to Peru, Pierre Bouguer conducted two experiments confirming Newtonian gravitational attraction and estimating the mean density of the Earth. One set of experiments determined the variation in gravity with altitude using a pendulum at sea level, Quito (2,860 m) and the summit of Pichincha (4,784 m). Qualitatively correct, Bouguer reported a smaller decrease in gravity than that predicted from altitude increase alone, but he calculated that the mean density of the Earth was nearly five times that of the near-surface rocks, an overestimate by a factor of at least two. The better reported experiment was an attempt to detect the deflection of the vertical near the mountain Chimborazo. There was a large difference between Bouguer's predicted plumb-line deflection, 103", and that which he and La Condamine measured, just 7". I have investigated both experiments using a digital elevation model to compute the vertical and horizontal components of the gravity field caused by topography, and include the regional gravity signature of the Andean crustal root. The modelling indicates not only that Bouguer's pendulum measurements were extremely accurate, but also that his observations allow a good determination of the significant isostatic effect. In contrast, on Chimborazo, contrary to recent suggestions, isostatic effects are negligible, and Bouguer's deflection was, within error, in line with the modelled plumb-line deflection from topography. Both Bouguer's pendulum and plumb-line measurements were reliable and therefore he should now be redeemed from any inference of failure.

The mystery of Copernicus’ star catalogue (The second part) The system of time and determination of the Earth’s triple motion

2020 ◽  
Vol 960 (6) ◽  
pp. 56-64
Author(s):  
S.A. Tolchelnikova
Keyword(s):  
Mean Value ◽  
Time System ◽  
Star Catalogue ◽  
The Earth ◽  
Mechanical Models ◽  
The Mean ◽  
Axis Rotation ◽  
The One ◽  
The Universe

Objecting to those who consider Copernicus’s work as repeating the achievements of Antiquity, we pay attention to his determination of uniform time necessary for applying any mathematical theory in particular, the one describing the observed uneven movements through a composition of circular and uniform rotations. Using the Egyptian year of 365 solar days, Copernicus analyzed the observations for the period from the first Olympiad up to his own observations. Generalizing the results of observations of two millennia and reducing them to the unique time system enabled his explaining the observed precession of equinoxes, and changes in the angle of inclination of the Earth’s equator to ecliptic by the lag of the Earth’s center rotation from that of its axis, simultaneously to exclude empty spheres from the medieval mechanical models of the Universe. Analyzing the observations of the period 4 times longer than that of Ptolemy, Copernicus managed to obtain the mean value of precession and the period of the Earth axis rotation practically coinciding with modern determinations. The proof of “the triple motion of the Earth” was necessary for affirmation of heliocentric system of the world.

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