The carbon of lighting gas, when the flames are sounding, is certainly almost entirely eliminated—in fact, it forms upon the interior surface of the sounding-tube at and below the height of the flames a very visible deposit of carbon, which increases while the air of the tube vibrates. I can now affirm that the pyrophone is in a condition to act as well with the illuminating gas as with pure hydrogen. The phenomenon of interference is produced exactly in the same condition with the two gases, the same flames occupy the same position in the tube, that is, the third part of the tube s length measured from the base. In addition to the phenomenon of interference, I believe I shall be able to describe a novel process by aid of which the sound produced by burning flames in a tube can be made to cease.
"Supposing that one or several flames, placed in a tube a third of its height (measured from its base), determine the vibration of the air contained in this tube; if a hole is pierced at the one-third of the tube, counted from the upper end, the sound ceases. This observation might be applied to the construction of a musical instrument, which will be a species of flute, working by singing-flames. Such an instrument, from a musical point of view, will be very imperfect, because the sound will not be so promptly or sharply stopped as when the phenomenon of interference is employed. If, instead of making the hole at the third, it is made at a sixth, the sound will not cease, but it will produce the sharp of the same note. In all these experiments I have clearly detected the formation of ozone while flames cause the air in the tube to vibrate. The presence of this body can, moreover, be ascertained by chemical reagents scientifically known."—Given before the Académie des Sciences, December 7, 1874.
Prof. Tyndall, at a lecture on January 13th, at the Royal Institution, showed experiments, according to the new principle, with an apparatus of nine flames, which worked during the evening in tubes of different sizes.—Journal of the Society of Arts.
| ANIMAL PHOSPHORESCENCE. |
AMONG the marvels which excite the admiration of the student of Nature, not the least strange is the group of phenomena known under the name of Animal Phosphorescence. We are so accustomed to associate light with heat, and to consider that fire of some kind is necessary to its production, that the imagination is appealed to with unusual force, when we find light proceeding from the body of a living animal Yet, it is well known that the emission of light is not an uncommon characteristic among the members of the invertebrate divisions of the animal kingdom. Travelers have often expatiated on the beauty of the scenes which they have witnessed in the tropics, when the seas or forests have seemed to be illuminated by innumerable sparks of fire; and recent discoveries have shown that the luminous quality is even more common than was previously supposed. During the dredging expeditions of H. M. S. Porcupine in the years 1869 and
