80 Notes and Memoranda. 



over its interior. Then make the tube vibrate longitudinally, which may be done 

 by rubbing one end with a moist cloth, and the powder will unite at certain points, 

 exhibiting the spiral nodes of Savart. ^If, after the lycopodium is applied, the 

 tube is closed at both ends, and fixed by one or two bands (noends), the powder 

 does not assemble at the spiral nodes, but assumes a peculiar arrangement at the 

 bottom of the tube. Periodical accumulations are remarked, composed of a series 

 of transverse layers, separated by vacant spaces. By filling the tube with different 

 gases, the length of the waves exhibited by the lycopodium will be found to vary 

 in proportion to the velocities with which they conduct sound. 



Peteoleum in Sicily. — Seven springs are said to have been discovered in 

 Sicily, which it is intended to work. 



Feiction of Celestial Bodies and Ethee. — M. de Fonvielle has a curious 

 paper in Cosmos on this subject. The atmospheres of rotating bodies like the 

 sun or planets must exert a friction on the ether of those surrounding them. The 

 friction of the sun's atmosphere against this ether he estimates at thirty times 

 that of our earth, and says, " other things being equal, the bigger a celestial body, 

 the more the temperature of its surface will be raised by friction against the matter 

 in space, and the greater the probability that this matter will be the seat of 

 energetic reactions and combinations with the rotating bodies' atmosphere." 



A Spontaneous Geneeation Expeeiment. — M. Donne states, Comptes Hen- 

 dies (Jan., 1867), that he makes a small hole in an egg with an awl, previously 

 made red hot. He pours out about a third of the egg's contents, fills it up with 

 boiling distilled water, closes the aperture with wax, and keeps the egg in his 

 room at a temperature of 17° to 24° C. In five days he finds the egg-matter 

 swarming with vibrions. 



Eyes of Cateepillaes. — M. Hermann Landois states that all kinds of cater- 

 pillars possess six eyes on each side of their heads, immediately below the 

 articulation of the mandibles. The cornea he finds to be divided in three seg- 

 ments, each exhibiting its proper curvature. Below the chitinous stratum of each 

 cornea he observes a sphereoidal chrystalline lens, formed of striated and un- 

 cleated fibres concentrically arranged, and below these lenses he notices a 

 diaphragm or iris composed of about thirty-five contractile fibres, and below the 

 iris what is known as a " crystalline body," which seems to consist of terminal 

 optical fibres. He regards these caterpillar eyes as intermediate between simple, 

 and compound facetted, eyes, and proposes to call them " compound ocelli." — 

 ZeitscJirift fur Zoologie. — Archives des Sciences. 



Molectjlae Foece in Liquids. — M. G-. Van des Mensbrugghe referring 

 to some experiments of M. F. Plateau states that if a vessel, about ten centimetres 

 wide, is three parts filled with water, held in front of an open window at least 

 six metres from the ground, and suddenly acted upon by a lateral shock, the fluid 

 in falling will form bubbles, the biggest of which are generally five or six centi- 

 metres in diameter. He tried various liquids : the bubbles of alcohol soon break, 

 fatty oils do not, from their viscosity, give a thin sheet, and their bubbles are 

 small. In other experiments he places a globule of mercury about half a milli- 

 metre in diameter on the blade of a knife, and gradually, by immersing the knife, 

 brings the mercury in contact with the surface of the water, on which it will float 

 and exhibit the phepomena of capillarity. The depression of the concave 

 meniscus is found to be very large in proportion to the size of the globule. The 

 attraction of floating bodies for each other may be shown by floating several of 

 these mercury globules. — Pagg. Ann. Archives des Sciences. 



The Planet Maes. — The remarks in the fourth paragraph of my paper on 

 Mars apply to Figs. 1 and 2, as originally drawn. The artist having reduced the 

 scale by one-half, one-sixteenth of an inch corresponds to 4,000,000 miles. » The 

 reduction has been faithfully effected, save that, in Fig. 2, the short lines sur- 

 mounted by arrow-heads have been left unreduced. I need scarcely say that I 

 Bhould have thrown the two figures into one, had I adopted the reduced scale. 

 In the smaller globe of Fig. 3, the lower cusp of the shaded part should fall as 

 much to the right of the line mm' as the upper cusp falls to the left. It will be 

 seen that the curve of the inner boundary would brijig the cusp to the place men- 

 tioned, but that this curve has been slightly deviated from, close to the lower 

 cusp. It. A. Peoctoe. 



