Part 6 (1/2)

APPENDIX II.

Page 23; note at line 3. Prof. Osborne Reynolds made the interesting remark (_Collected Papers_, Vol. ii., p. 154), ”That if solid matter had certain kinds of internal motions, such as the box has, pears differing, say, from apples, the laws of motion would not have been discovered; if discovered for pears they would not have applied to apples.”

Page 38; note at line 8. The motion of a rifle bullet is therefore one of precession about the tangent to the path. The mathematical solution is difficult, but Prof. Greenhill has satisfied himself mathematically that air friction damps the precession, and causes the axis of the shot to get nearer the tangential direction, so that fig. 10 ill.u.s.trates what would occur in a vacuum, but not in air. It is probable that this statement applies only to certain proportions of length to diameter.

Page 129; note at line 5. Many men wonder how the ether can have the enormous rigidity necessary for light transmission, and yet behave like a frictionless fluid. One way of seeing how this may occur is to imagine that when ordinary matter moves in the ether it only tends to produce motion of translation of the ether particles, and therefore no resistance. But anything such as light, which must operate in turning axes of rotating parts, may encounter enormous elastic resistance.

_Richard Clay & Sons, Limited, London and Bungay._

PUBLICATIONS

OF THE

SOCIETY FOR PROMOTING CHRISTIAN KNOWLEDGE.

THE ROMANCE OF SCIENCE.

Small post 8vo, cloth boards.

COAL, AND WHAT WE GET FROM IT. By Professor R. MELDOLA, F.R.S., F.I.C.

With several Ill.u.s.trations. 2s. 6d.

COLOUR MEASUREMENT AND MIXTURE. By Sir W. DE W. ABNEY, K.C.B., R.E., F.R.S. Numerous Ill.u.s.trations. 2s. 6d.

DISEASES OF PLANTS. By Professor MARSHALL WARD. Numerous Ill.u.s.trations.

2s. 6d.

OUR SECRET FRIENDS AND FOES. By PERCY FARADAY FRANKLAND, Ph.D., B.Sc.

(Lond.), F.R.S. Ill.u.s.trated. 3s.

SOAP-BUBBLES, AND THE FORCES WHICH MOULD THEM. By C. V. BOYS, A.R.S.M., F.R.S. Ill.u.s.trated. 2s. 6d.

SOUNDING THE OCEAN OF AIR. By A. LAWRENCE ROTCH, S.B., A.M. Numerous Ill.u.s.trations. 2s. 6d.

SPINNING TOPS. By Professor J. PERRY, M.E. With several Ill.u.s.trations.

2s. 6d.

THE MAKING OF FLOWERS. By the Rev. Professor GEORGE HENSLOW, M.A., F.L.S., F.G.S. With Ill.u.s.trations. 2s. 6d.

THE STORY OF A TINDER-BOX. By the late CHARLES MEYMOTT TIDY, M.B., M.S., F.C.S. Numerous Ill.u.s.trations. 2s.

TIME AND TIDE. A Romance of the Moon. By Sir ROBERT S. BALL, LL.D. With Ill.u.s.trations. 2s. 6d.

THE BIRTH AND GROWTH OF WORLDS. By the late Professor GREEN, F.R.S.

With Ill.u.s.trations. 1s.

THE SPLASH OF A DROP. By Professor A. M. WORTHINGTON, F.R.S. Numerous Ill.u.s.trations. 1s. 6d.