14 COSMOS. 



nomical measurement of a degree, pendulum experiments, 

 and calculations of the inequalities in the latitude and longi- 

 tude of the moon. In the application of the first method 

 two separate processes are required, namely, measurements 

 of a degree of latitude on the arc of a meridian, and mea- 

 surements of a degree of longitude on different parallels. 



Although seven years have now passed since I brought 

 forward the results of Bessel's important labours, in refer- 

 ence to the dimensions of our globe, in my General Delineation 

 of Nature, his work has not yet been supplanted by any one 

 of a more comprehensive character, or based upon more recent 

 measurement's of a degree. An important addition and great 

 improvements in this department of inquiry may, however, 

 be expected on the completion of the Russian geodetic mea- 

 surements, which are now nearly finished, and which, as they 

 extend almost from the North Cape to the Black Sea, will 

 afford a good basis of comparison for testing the accuracy of 

 the results of the Indian survey. 



According to the determinations published by Bessel in 

 the year 1841, the mean value of the dimensions of our 

 planet was, according to a careful investigation 7 of ten mea 



early death has proved a severe loss to science, in PoggendorfFs Annalen 

 der Physilc und Chemie. Bd. xxxiii, 1834, s. 229233. 



7 The first accurate comparison of a large number of geodetic mea- 

 surements (including those made in the elevated plateau of Quito, two 

 East Indian measurements, together with the French, English, and 

 recent Lapland observations) was successfully effected by Walbeck, at 

 Abo, in 1819. He found the mean value for the earth's ellipticity to be 

 3oa 1 76l , and that of a meridian degree 57009.758 toises, or 324,628 feet. 

 Unfortunately his work, entitled De Forma et Magnitudine Telluris has 

 not been published in a complete form. Excited by the encouragement 

 of Gauss, Eduard Schmidt was led to repeat and correct his results in his 

 admirable Handbook of Mathematical Geography, in which he took into 

 account both the higher powers given for the ellipticity, and the lati- 

 tudes observed at the intermediate points, as well as the Hanoverian 

 measurements and those which had been extended as far as Formentera 

 by Biot and Arago. The results of this comparison have appeared in 

 three forms, after undergoing a gradual correction, namely, in Gauss's 

 JBestimmung der Breitenunterschiede von Gottingen undAltona 1828, s. 82 ; 

 in Eduard Schmidt's Lehrluchdcr Mathem. und Phys. Geographic, 1829, 

 Th. 1, s. 183, 194 199; and lastly in the preface to the latter work 

 (s. 5). The last result is, for a meridian degree 57008.655 toises, or 

 324,261 feet ; for the ellipticity, zWJ^^ra- Bessel's first work of 1 830 had 

 been immediately preceded by Airy's treatise on tioa Figure of the Earth, 



