In the _Liverpool Mercury_ of May 23, 1851, the following letter appeared:--“The supposed manifestation of the Rotation of the Earth.--The French, English, and European continental journals have given publicity to an experiment made in Paris with a pendulum; which experiment is said to have had the same results when made elsewhere. To the facts set forth no contradiction has been given, and it is therefore to be hoped that they are true. The correctness of the inferences drawn from the facts is another matter. The first position of these theorists is, that in a complete vacuum beyond the sphere of the Earth’s atmosphere, a pendulum will continue to oscillate in one and the same original plane. On that supposition their whole theory is founded. In making this supposition the fact is overlooked that there _is no vibratory motion_ unless through atmospheric resistance, or by force opposing impulse. Perpetual progress in rectilinear motion may be imagined, as in the corpuscular theory of light; circular motion may also be found in the planetary systems; and parabolic and hyperbolic motions in those of comets; but vibration is artificial and of limited duration. No body in nature returns the same road it went, unless artificially constrained to do so. The supposition of a permanent vibratory motion such as is presumed in the theory advanced, is _unfounded in fact_, and absurd in idea; and the whole affair of this proclaimed discovery falls to the ground. It is what the French call a ‘mystification’--anglice a ‘humbug.’ Liverpool, 22nd May, 1851.” “T.” Another writer declared that he and others had made many experiments and had discovered that the plane of vibration had nothing whatever to do with the meridian longitude nor with the Earth’s motion, but followed the plane of the magnetic meridian. “A scientific gentleman in Dundee recently tried the pendulum experiment, and he says--‘that the pendulum is capable of showing the Earth’s motion I regard as a _gross delusion_; but that it tends to the _magnetic meridian_ I have found to be a fact.’”[38] [38] _Liverpool Journal_, May 17, 1851.