

NATURAL PHILOSOPHY. 



[Lesson IX. 



,md so on until No. 5, in which the 

 fluid is raised to a considerable height ; it 

 being an established rule, that tlu- smaller 

 ti.e lube, the gre tier will be the height of 

 the surface of the fluid. 



107. T. Give me a familiar example 

 of capillary attraction .' 



P. [Experiment 18.] I have a basin of 

 water here, and a skein of cotton. Yon 

 observe that one end of the cotton is im- 

 mersed in the water, and if this basin is left 

 sufficiently long in its place, the whole of 



the water will be extracted from tli 



by the force of capillary attraction, and fall 



into the tumbler I now place beneath. 



CLNKKAL QUESTIONS ON LESSON VIII. 

 1. What is the attraction of cohesion? 

 '1. What are its effects I 



3. How can you prove the property ? 



4. "What is capillary attraction? 



5. How does it act ? 



6. Prove that it exists. 



LESSON IX. 



RECAPITULATION, &c. When a plate falls it breaks into several pieces ; the attrac- 

 tion of cohesion being overcome by the force of the fall ; and when a piece of wood 



is split with a chisel, the power of cohesion is 

 overcome by the force employed. These are 

 examples we may witness every day. We have 

 also learned that the force of gravitation 

 may be overcome by the force of capillary 

 attraction, (from capilla, the Latin for a hair), 

 and that fluids may be raised above their levels 

 by its power ; this we proved by tubes of 

 different diameters being immersed in a 

 coloured fluid, but we can demonstrate it also 

 by another simple experiment, [Experiment 

 19.] Take two sheets of glass of the same 

 size, and place them in the contact at a, b, 

 but separate them by means of a piece of cork (c) at d, e. Immerse them in a solution 

 of logwood, or ink and water, contained in the trough/. It will then be found that the 

 fluid will ascend higher between the glasses at a, b, than at e, where it is scarcely above 

 the level, because the attraction is greater at a, b, than at e. You observe that the 

 fluid is curved from a to c ; this curve has received the name of the hyperbola. Wlu-n 

 we consider the other branches of science, we will enter into the phenomena attending 

 chemical, magnetic, and electrical attraction, which do not essentially pertain to 

 Natural Philosophy. 



QUESTIONS. 



Fig. 11. 



108. r. What is meant by REPULSION. 



7 J . It is that power by which the par- 

 ticles of bodies, or the bodies themselves, 

 are made to recede from one another. 



109.T. Does the power of repulsion 

 exist in all bodies ? 



/-*. Yes ; all the particles of material 

 substances possess the power of attraction 

 and repulsion. 



110. 71 What is the great agent of 

 rapulti 



P. Caloric or heat, which pervades all 

 things. 



111. T. What is caloric? 



P. It has been called an imponderable 

 body, because it does not cause any per- 

 ceptible difference in the weight of any 

 body. 



