Spinning Tops Part 10

COLONIAL CHURCH HISTORIES.

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DIOCESE OF MACKENZIE RIVER, by the Right Rev. W. C. BOMPAS, D.D., Bishop of the Diocese. _2s._

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HISTORY OF THE CHURCH IN EASTERN CANADA AND NEWFOUNDLAND, by the Rev.

J. LANGTRY. _3s._

THE CHURCH IN THE WEST INDIES, by the Rev. A. CALDECOTT, B.D. _3s. 6d._

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Notes

[1] The _Operatives' Lecture_ is always well advertised in the streets beforehand by large posters.

[2] Bulwer Lytton's _Coming Race_.

[3] The gla.s.s vessel ought to be broader in comparison with its height.

[4] In 1746 Benjamin Robins taught the principles of rifling as we know them now. He showed that the _spin_ of the round bullet was the most important thing to consider. He showed that even the bent barrel of a gun did not deflect the bullet to anything like the extent that the spin of the bullet made it deflect in the opposite direction.

[5] NOTE.--In Fig. 16 the axis is shown inclined, but, only that it would have been more troublesome to ill.u.s.trate, I should have preferred to show the precession occurring when the axis keeps horizontal.

[6] When this lecture containing the above statement was in the hands of the printers, I was directed by Prof. Fitzgerald to the late Prof. Jellet's _Treatise on the Theory of Friction_, published in 1872, and there at page 18 I found the mathematical explanation of the rising of a top.

[7] Roughly, the _Inertia_ or _Ma.s.s_ of a body expresses its resistance to change of mere translational velocity, whereas, the _Moment of Inertia_ of a body expresses its resistance to change of rotational velocity.

[8] It is a very unlikely, and certainly absurd-looking, hypothesis, but it seems that it is not contradicted by any fact in spectrum a.n.a.lysis, or even by any probable theory of the const.i.tution of the interstellar ether, that the stars are merely images of our own sun formed by reflection at the boundaries of the ether.

[9] Sir William Thomson has performed this.

[10] It must be remembered that in one case I speak of the true north, and in the other of the magnetic north.

[11] Rotating a large ma.s.s of iron rapidly in one direction and then in the other in the neighbourhood of a delicately-suspended magnetic needle, well protected from air currents, ought, I think, to give rise to magnetic phenomena of very great interest in the theory of magnetism. I have hitherto failed to obtain any trace of magnetic action, but I attribute my failure to the comparatively slow speed of rotation which I have employed, and to the want of delicacy of my magnetometer.

[12] I had applied for a patent for this system of signalling some time before the above words were spoken, but although it was valid I allowed it to lapse in pure shame that I should have so unblushingly patented the use of the work of Fitzgerald, Hertz, and Lodge.

[13] How to see by electricity is perfectly well known, but no rich man seems willing to sacrifice the few thousands of pounds which are necessary for making the apparatus. If I could spare the money and time I would spend them in doing this thing--that is, I think so--but it is just possible that if I could afford to throw away three thousand pounds, I might feel greater pleasure in the growth of a great fortune than in any other natural process.

[14] Probably first described by Mr. Brennan.

[15] The weight of Mr. Brennan's loaded wagon is 313 lb., including gyrostats and storage cells. His two wheels weigh 13 lb. If made of nickel steel and run at their highest safe speed they would weigh much less.