W. CROOKES.
CONTENTS.
| LECTURE I. | |
| PAGE | |
| THE FORCE OF GRAVITATION, | [13] |
| LECTURE II. | |
| GRAVITATION—COHESION, | [44] |
| LECTURE III. | |
| COHESION—CHEMICAL AFFINITY, | [72] |
| LECTURE IV. | |
| CHEMICAL AFFINITY—HEAT, | [99] |
| LECTURE V. | |
| MAGNETISM—ELECTRICITY, | [122] |
| LECTURE VI. | |
| THE CORRELATION OF THE PHYSICAL FORCES, | [147] |
| LIGHT-HOUSE ILLUMINATION—THE ELECTRIC LIGHT, | [173] |
| NOTES, | [195] |
| [Book Catalogue] | |
THE
VARIOUS FORCES OF NATURE.
LECTURE I.
THE FORCE OF GRAVITATION.
It grieves me much to think that I may have been a cause of disturbance in your Christmas arrangements[1], for nothing is more satisfactory to my mind than to perform what I undertake; but such things are not always left in our own power, and we must submit to circumstances as they are appointed. I will to-day do my best, and will ask you to bear with me if I am unable to give more than a few words; and as a substitute, I will endeavour to make the illustrations of the sense I try to express as full as possible; and if we find by the end of this lecture that we may be justified in continuing them, thinking that next week our power shall be greater,—why, then, with submission to you, we will take such course as you may think fit,—either to go on, or discontinue them; and although I now feel much weakened by the pressure of illness (a mere cold) upon me, both in facility of expression and clearness of thought, I shall here claim, as I always have done on these occasions, the right of addressing myself to the younger members of the audience. And for this purpose, therefore, unfitted as it may seem for an elderly infirm man to do so, I will return to second childhood and become, as it were, young again amongst the young.
Let us now consider, for a little while, how wonderfully we stand upon this world. Here it is we are born, bred, and live, and yet we view these things with an almost entire absence of wonder to ourselves respecting the way in which all this happens. So small, indeed, is our wonder, that we are never taken by surprise; and I do think that, to a young person of ten, fifteen, or twenty years of age, perhaps the first sight of a cataract or a mountain would occasion him more surprise than he had ever felt concerning the means of his own existence,—how he came here; how he lives; by what means he stands upright; and through what means he moves about from place to place. Hence, we come into this world, we live, and depart from it, without our thoughts being called specifically to consider how all this takes place; and were it not for the exertions of some few inquiring minds, who have looked into these things and ascertained the very beautiful laws and conditions by which we do live and stand upon the earth, we should hardly be aware that there was anything wonderful in it. These inquiries, which have occupied philosophers from the earliest days, when they first began to find out the laws by which we grow, and exist, and enjoy ourselves, up to the present time, have shewn us that all this was effected in consequence of the existence of certain forces, or abilities to do things, or powers, that are so common that nothing can be more so; for nothing is commoner than the wonderful powers by which we are enabled to stand upright—they are essential to our existence every moment.