Sometime prior to 1901, the French Government, wishing to determine more accurately the actual size of the Earth, so that they could revise and refine their calculations regarding the distance to the sun, hit on a way to measure the difference in distance apart at the top of two lines perpendicular to the surface of the Earth and the bottom of those same two lines. They wanted a pair of lines long enough to give them an appreciable measurement. Obviously they could not erect two parallel poles a mile high, but they did feel they could suspend two plumb bobs a mile deep into a mine shaft, and thus be able to measure the distance apart at the top and the distance apart at the bottom, which would be slightly less. They wanted to know exactly how much less.

The result of these tests were very strange. So strange that the French Geodetic scientists contacted the scientists of the American Geodetic Survey and conveyed their results to them, with the request that similar tests be conducted in this country. Officially, nothing was done for some years. But in 1901, one of the Geodetic surveyors happened to be working in the vicinity of the Tamarack mines near Calumet, Michigan. He contacted the chief engineer at Tamarack, and informed him of the information transmitted by the French government.

Two mine shafts were selected, and plumb lines exactly 4250 feet long were suspended in each mine. At the end of these lines a sixty pound bob was hung. In order to prevent movement through a horizontal direction, each bob was suspended in a tank of oil placed at the bottom of the mine shafts. In this way, it was reasoned, magnetic forces could not affect them. The lines used to suspend the bobs were No.24 piano wires. For twenty-for hours the lines were allowed to hang, so that there would be no possibility of movement from putting them in place still remaining in the lines. The measurements were begun.

It was then that it was discovered that the French Geodetic engineers had not made a mistake. Careful re-checking proved that the lines, contrary to expectations, were farther apart at the bottom than at the top!

There can be only one implication to such a strange result - the center of gravity is not, as previously believed, at the center of the Earth.

Greatly puzzled, and not a little disturbed, the Tamarack engineer sent for Professor McNair of the Michigan College of Mines. With McNair there to check his results, the experiment was repeated, the measurements gone over again, and both men were convinced that no error had been made. Professor McNair suggested that the plumb bobs be changed to a non-magnetic metal to overcome any possibility of magnetic attraction or repulsion due to magnetic ore body nearby. But when this was done, the same figures were arrived at. If magnetic influences had been at work, they would have varied with different metals, but they did not.

Now, suggested McNair, it would be a good idea to prevent air currents from traveling up and down the mine shafts which might be affecting the plumb lines. Thus, both mine shafts were sealed at the top. Once more the figures remained the same.

Professor McNair, when questioned, stated for publication that he had proved that magnetic attraction from the Earth or the sides of the shaft did not cause the strange divergence. Then he went back to the Michigan College of Mines and wiped the whole thing from his mind.

A second series of experiments were conducted at Calumet. This time two elevator shafts into the mine were used instead of one, those numbered two and fife. These two were 4250 feet apart, and were also 4250 feet deep. They were connected at the bottom by a perfectly straight transverse tunnel. Now plumb bobs were hung in each shafts, and measurements were made. This time it was found that the plumb lines were 8.22 inches farther apart at the bottom than at the top. It did not take the Tamarack engineer long to discover that this figure exactly represents the divergence that would be necessary to complete a 360 degree spherical circumference. There was only one difficulty - as expressed by the plumb lines, it would be the circumference of the inside of a sphere, and not the outside! Further, the center of gravity, as expressed by the angles formed by the plumb lines, would be approximately 4,000 miles out in space!

Obviously this could not be true, because if the Chinese were to make calculations based on a similar pair of mine shafts in their country, on the opposite side of the globe, the center of gravity would be found to be 4000 lines in the other direction.

The Earth is a sphere (with certain very minor irregularities). We live on the outside of it. The Moon circles the Earth, and the Earth circles the Sun. Some force holds them all in orbit and their relationships to each other. It is said that gravitation is that force. It is said the Moon's orbit is maintained because the attraction of mass of both bodies is exactly counterbalanced by centrifugal force. The Earth system is maintained in its orbit about the sun by the same delicate balance. Could it be that there is no such thing as "attraction of mass?"

Or could it be that the Earth is really some other shape - even hollow?