Per centum of the weight of steam generated in the boiler, condensed in the 1st cylinder at the end of the stroke of its piston, exclusive of the condensation due to the development of power by the expanded steam alone,

Per centum of the weight of steam generated in the boiler, condensed in the 24 cylinder at the end of the stroke of its piston, exclusive of the condensation due to the development of power by the expanded steam alone,

Per centum of the weight of steam generated in the boiler, condensed in the 3d cylinder at the end of the stroke of its piston, exclusive of the condensation due to the development of the power by the expanded steam alone,

COMBUSTION.

Pounds of coal consumed per hour per square foot of grate surface,

9.0213

11.5624

Registering Apparatus for Marine Cables.-The most perfeet apparatus which has hitherto appeared for giving graphic signals upon the great submarine lines of cable is Sir Wm. Thomson's syphon recorder. There would be a great advantage in a telegraph which would register the signals of the mirror galvanometer. Paul Samuel proposes to use two selenium elements upon the screen where the light from the galvanometer is reflected: one at the right, the other at the left. Whenever one of them is illuminated its increased conductibility will enable it to act as a relay upon an electro-magnet, for marking upon a paper band the points and dashes of the Morse alphabet. He recommends the use of paper dipped in iodide of potassium, and of a triangle which will be moved so that the point will be controlled by one of the selenium elements and the base by the other; in the former case a dot will be produced, in the latter a dash.-Les Mondes.

WHOLE NO. VOL. CXII.-(THIRD SERIES, Vol. lxxxii.)

C.

18

RADIO-DYNAMIC FACTS.

By PLINY EARLE CHASE, LL.D.
Professor of Philosophy in Haverford College.

Before proceeding to demonstrate the fundamental propositions of photodynamics it may be well to give a list of some of the most important FACTS which have been added to the repertory of science by investigating the laws of action and reaction in elastic media. The original announcements of discovery may be found in the "Proceedings of the American Philosophical Society," unless otherwise stated. 1. The importance of the equations of "nascent" or dissociative velocity, v = gt2 gt, and of nascent modulus, h = ; t representing 4 the time of cosmical, molecular, or atomic rotation, and g representing the acceleration of a central force. Dec. 18, 1863.

2

2. Sun's annual and Earth's daily disturbances of atmospheric elasticity furnish data for estimating the distance and relative masses of the two disturbing bodies. Dec. 18, 1863.

3. Modification of the daily distribution of solar heat by cyclical elasticity and barometric pressure. March 4, 1864.

4. Mechanical modification of electric and magnetic currents. April 1, 1864; Oct. 6, 1865.

5. Oscillations produced by gravitating disturbances of molecular elasticity. April 1, 1864.

6. Polarizing influences of thermal convection and radiation. April 15, 1864.

7. Resemblance between lunar-monthly and solar-daily barometric fluctuations. June 17, 1864. Proc. Roy. Soc., June 16, 1864.

8. Combined influences of rotation, variations of temperature and vapor, solar and lunar attraction, and æthereal oscillations "moving with the rapidity of light," upon barometric fluctuations. July 15,

1864.

9. Numerical relations of gravity and magnetism. Oct. 21, 1864. 10. Resemblance between solar and lunar magnetic and atmospheric tides. Dec. 16, 1864.

11. Inverse relation of specific magnetism to coefficients of dilatation. May 19, 1865.

12. Control of magnetic needles by artificial currents resembling the normal atmospheric currents. Oct. 6, 1865.

13. Relations of temperature to gravity and density. Sept. 21, 1866.

14. Relation of terrestrial gravity to the velocity of light. Sept. 21, 1866.

15. Approximate equality in the influence of solar radiation and of atmospheric currents upon fluctuations of temperature. Feb. 1, 1867.

16. Demonstration of lunar influence upon rainfall by comparing different periods of observation at the same station. Dec. 4, 1868; Aug. 18, 1871; etc.

17. Equivalence of solar "nascent" or dissociative velocity (1) to the velocity of light. April 2, 1869.

18. Cosmical relations of light to gravity. April 2, 1869.

19. Frequency of anticyclonic storms and of local cyclones in general anticyclones. March 3 and 17, 1871.

20. Resemblance of atmospheric, magnetic and oceanic currents. April 7, 1871.

21. Identity of law in cosmical and molecular forces. Feb. 16,

1872.

22. Simple relations of explosive energy to Sun's mass and distance. Feb. 16, 1872.

23. Ratio of vis viva of wave-propagation to vis viva of oscillating particles. Feb. 16, 1872.

24. Influence of centres of oscillation and of the factor of linear ris viva, 9, on planetary masses, distances and cyclical motions. March 1, 1872.

25. Tendency of elastic vibrations to produce harmonic vibrations, illustrated by terrestrial rotation, lunar distance, lunar revolution and the velocity of light. April 5, 1872.

26. The same tendency illustrated by apsidal and mean planetary positions and eccentricities, by solar, planetary and lunar rotations, and by the sun-spot-cycle of 1107 years. May 16, 1872.

27. Nebula-rupturing velocities acquired by subsidence from nr to

28. Evidences of parabolic projection between Sun and the nearest fixed star. Sept. 20, 1872.

29. Harmony of stellar and planetary positions with Sun's gravitating reaction against luminous undulation. Sept. 20, 1872.

30. Lunar influence on rainfall less affected by locality than solar. Nov. 1, 1872.

31. Influence of the circular ratio, , upon planetary positions. Feb.

7, 1873.

32. Increased symmetry introduced by the supposed failure of "Bode's Law." March 7, 1873.

33. Musical intervals in the Fraunhofer lines. March 21, 1873. 34. Musical intervals in planetary positions. April 4, 1873. 35. Harmonic indications of intra-Mercurial planets. May 2,

1873.

May 2, 1873.
Oct. 3, 1873.

36. Harmonic correlations of planetary mass. 37. Confirmation of harmonic prediction. 38. The harmonic planetary progression closer than any other that has been pointed out. Oct. 3, 1873.

39. Mean proportionality of perihelion parabolic velocity between normal velocity of solar oscillation and the velocity of light. May 15, 1874.

40. Harmonic grouping of planets into pairs. May 15, 1874. 41. Harmonic influence of the centre of gravity of Sun and Jupiter on planetary masses, positions and motions. May 15, 1874. 42. Influence of luminous undulation on the secular eccentricity of Jupiter, terrestrial gravity and cosmical masses. Jan. 1, 1875. 43. Analogous equations in general physics, electricity, chemistry

and cosmogony. June 18, 1875.

44. Circular ratio of velocity of dissociation to velocity of cohesion. June, 18, 1875.

45. Estimate of Sun's mass and distance from the tidal relations of magnetism and gravitation. June 18, 1875.

46. Combined planetary evidences of Fourier's theorem and of a universal elastic medium. Aug. 20, 1875.

47. Different atmospheric and nucleal rupturing tendencies in Herschel's statement of the nebular hypothesis, and consequent misapprehension of the laws of nucleal condensation. Sept. 17, 1875.

48. The nucleal radius, in a rotating condensing nebula, varies as the power of Laplace's limiting radius, or radius of possible atmosphere. Sept. 17, 1875.

49. Mathematical deduction of the ratio of heat under constant

volume to heat under constant pressure from the vis vira of gaseous volume and of uniform velocity. Dec. 3, 1875.

50. Harmonies of products and powers of planetary mass and distance. Dec. 3, 1875.

51. Various confirmations of Herschel's theory of subsidence. April 21, 1876.

52. Evidences of parabolic influence in chemical atomicity. Feb.

2, 1877.

53. Various nebula-rupturing tendencies of "subsidence." July 20, 1877.

54. Identity of law in spectral lines and planetary arrangement. Aug. 24, 1877.

55. Confirmation of Herschel's nebular theory by the moons of Mars. Jan. 18, 1878.

56. Harmonic wave-lengths in chemical elements. Jan. 18, 1878. 57. Harmonic arrangement of satellite-systems. Jan. 18, 1878. 58. Relation of planetary positions to the solar modulus of light. March 1, 1878.

59. The centre of greatest planetary condensation is in Earth's orbit; the nebular centre of planetary inertia, in Saturn's orbit; the centre of the Neptuno-Uranian nebula, in Jupiter's orbit. March 1, 1878.

60. Nine intra-Mercurial harmonic positions showing tendencies to synchronous oscillation and confirming harmonic prediction. Oct. 4,

1878.

61. Two additional confirmations of harmonic prediction. Feb. 21,

1879.

62. Harmonies of Lockyer's "basic lines." April 4, 1879.

63. Harmonic relations of the terrestrial day to the year. Dec. 19, 1879.

64. Relations between cosmical masses and positions. Jan. 2, 1880. 65. Various planetary relations between gravitating and luminous velocities. March 19, 1880.

66. Relation of ocean temperatures to Joule's equivalent. April 16, 1880.

67. Relations of chemical affinity to luminous and cosmical energies. April 16, 1880.

68. Evidences of subsidence at the outer surface, and of rupturing