EXPLANATION OF FIGURES.

PLATE I.

Fig. 1. A X. a flexible polarized axis, positive and negative at its opposite extremities. C, the same, in which the consecutive poles are united, the axis being thus bent into a circle, and the subtile matter formerly polarized now circulated. See p. 12. 2. Atoms. The under one invested by its sphere of subtile matter, the regions of attraction being represented by the four pencils crowning the angles.

3. A trigonal bipyramid formed by two atoms united by their bases. Hydrogen.

4. A pentagonal bipyramid formed by five atoms united by an edge. Carbon.

5. Eight atoms united so as to enclose an octædral cavity. Silicon. 6. Six atoms united so as to enclose two as in Fig. 3. or a cavity of the same form. Magnesium and Calcium.

7. Ten atoms united so as to enclose five as in Fig. 4. or a cavity of the same form. Sodium and Potassium.

8. Five triangular bipyramids (Fig. 3.) touching by an equatorial angle, and bent down so that the polar angles of one cohere to the equatorial angles of another, a form destitute of an axis. Oxygen.

9. An electro-positive form Fig. 4. united to a conformable electronegative form, Fig. 8. A particle of Carbonic Acid.

10. Two substances, Figs. 3 and 4 united, which, though both elec

tro-positive in relation to Fig. 8., are not equally so, and are therefore positive and negative in relation to each other, and capable of union. Light carburetted Hydrogen.

11. The same elements as in Fig. 10. united, so as to form a symmetrical particle. Olefiant gas.

12. Five triangular bipyramids (Fig. 3.) united by an edge. A combining particle of Nitrogen.

13. Two of Fig. 12. united so as to produce a symmetrical solid par

ticle. Animal nitrogen.

Fig. 14. The same as Fig. 13., the two particles adhering only by five equatorial angles. Atmospherical nitrogen.

15. The same as Fig 14. with the five equatorial cavities filled with
five of Fig. 4. to which they are conformable. Chlorine.

17. A substance resulting from the union of Figs. 3 and 15, which
are positive and negative in reference to each other Muriatic
acid.

16. Polarity developed by induction.

18. Figures illustrating the expansion and contraction of a fibre composed of spheroidal molecules in consequence of a change in the polarity of the particles.

19. An electro-negative molecule,

20. An electro-positive molecule,

See page 38.

22. A fragment of a perfect ray of the radiant medium (the atoms being represented almost contiguous, in order to shew their relationship), or a ray of common light.

24. A fragment of a singled or polarized ray, Fig. 22 consisting of
four such in transverse positions two and two.

25. Illustration of the phenomena of interference, see page 91.
26. An axis, prism or ray of light, singled or polarized by reflection
from a reflecting cone, by which an equator of light is de-
veloped polarized in a plane transverse to that of the axis, so far
as its light is polarized.

27. A diagram illustrating the cause of the constant ratio of the sines
in refraction.

28. A photomotive pile or pile of glass plates, for polarizing light.
29. One ray of common light parted into seven by one rhomboid of
Iceland crystal, copied from Malus.

30. The symmetry of common or perfect light destroyed by refraction
through a prism.

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