Though this determination came to a premature end at the commencement of the war by the cutting of the cable, and consequently the result could not possess the desired accuracy, nevertheless it was evident that the alteration is still too small to be detected with any certainty. The difference of the longitude of Cambridge-Greenwich was, in fact, found to be[1]:—
The oldest determination of 1866, for which I found 4 h. 44 m. 30.89 s., has been omitted, as it was alleged to be too inaccurate. It is certainly highly desirable that a new complete determination of longitude should be carried out, but the possibility must be reckoned with that the displacement is too small even then to be detectable with any degree of certainty.
But perhaps it will be possible to ascertain the displacement of North America by corresponding determinations of latitudes with Greenland. There certainly also exists the prospect, in the case of the difference of latitude of Madagascar and Africa, of measuring its alteration by repeated observations over not too lengthy a period.
Finally, reference should be made to the variation of the geographical latitudes of European and North American observatories. A. Hall[2] considered the following decrease of latitudes as proved:—Washington in 18 years about 0.47″; Paris in 28 years about 1.3″; Milan in 60 years about 1.51″; Rome in 56 years about 0.17″; Naples in 51 years about 1.21″; Königsberg (Prussia) in 23 years about 0.15″; Greenwich in
↑Compare the Jahresber. d. preusz. Geodät. Instituts in Vierteljahrsschr. d. Astron. Ges., 51, p. 139, as well as the Astronomical Journal, No. 673/674.
↑Günther, Lehrb. d. Geophysik., 1, p. 278. Stuttgart, 1897.
