Notes and Memoranda. 465 



place in the jet exactly as the molecules of a running liquid do." M. Tresca 

 thinks that operations of this kind may explain certain geological cases of intru- 

 sion of one rock into another. 



Thallic Alcohols. — M. Lamy describes in Comptes Rendus, No. 19, 1864, 



three alcohols containing thallium, two being liquids and one solid. Ethyl thallic 



C 4 H 5 I 

 alcohol, nm {■ O 2 , has a density exceeding three and a half times that of water, 



and its refractive and dispersive powers exceed those of bisulphide of carbon. 

 These alcohols are soluble in chloroform and ether ; water, or atmospheric moisture, 

 decomposes them qxiickly. Ethyl thallic alcohol is obtained by placing a con- 

 siderable mass of absolute alcohol under an air pump in a large flat vessel, and 

 beneath the liquid are leaves of thallium supported by a metallic gauze. A vacuum 

 is made to remove air and moisture, and then oxygen is introduced through tubes 

 containing pumice and sulphuric acid. At a, temperature of 20° or 25° C. the 

 thallium is rapidly transformed into a heavy oil that falls to the bottom of the 

 vessel containing the alcohol. A hundred grammes are easily obtained in twenty- 

 four hours, without touching the apparatus. This substance might be useful in 

 spectroscope inquiries. 



Eighty-Second Planet. — Dr. E. Luther saw a planet 11 mag. on 27th Nov., 

 A. R, 60" 32' ll"-3. D + 23° 41' 20"1, which he thought was new. His opinion 

 has been verified, and the new planet is named "Alkmene." 



Stab Eclipsed by Comet I. 1864. — Signor Cacciatore of the Palermo Ob- 

 servatory, states that on the 7th Aug., in the evening, he saw an 8-mag. star 

 eclipsed by the nucleus of the above comet. — Astron. Nacli. 



Dissociation oe Cabbonic Oxyde.— M. H. St. Claire Deville communicates 

 to the French Academy fresh researches into the phenomena which he terms 

 "dissociations." He observes that "water and carbonic acid, which at the mo- 

 ment of their formation develop a very high temperature, exhibit the apparently 

 paradoxical property of partially reducing themselves into their elements when 

 they are heated to a point considerably below that which determines their total 

 decomposition, or the combination of the simple bodies composing them." In 

 experimenting with carbonic oxyde, M. Deville causes that gas to pass through a 

 highly heated porcelain tube, through the middle of which runs a small thin 

 brass tube traversed by a current of cold water, which keeps it cool, while the 

 walls of the porcelain tube are hot enough to act upon the carbonic oxyde. By 

 this arrangement he partially decomposes the carbonic oxyde. A portion of car- 

 bon is deposited in the brass tube, which acts as a refrigerator, and the oxygen set 

 at liberty unites with the rest of the carbonic oxyde, and raises it to the condition 

 of carbonic acid. 



Atmospheees oe the Eaeth and Planets. — Comptes Rendus, No. 22, 1864, 

 contain a paper by M. Chacornac, On the Transparency of the Terrestrial Atmos- 

 phere and its Reflecting Rower. He states that when observing the transit of Saturn's 

 fourth satellite on 1st May, 1862, with the largest telescope in the Paris Observa- 

 tory, he obtained proof that the margin of the planet's disc is brighter than the 

 central region, and this seemed contrary to the phenomena presented by Jupiter, 

 whose satellites during transits appear bright spots near the margin, and dark 

 spots when traversing the central regions. This contrast he traces to the difference 

 of reflective power possessed by the two atmospheres. He then details experi- 

 ments and observations made to ascertain how the terrestrial atmosphere behaved. 

 When the sun is at its greatest height at summer noon, and the sky clear, he 

 found the greatest brilliancy near the horizon. This he states to be noticeable by 

 merely using a screen to shut out the sun and the surrounding aureole. For more 

 accurate observations he employed a small prismatic telescope, the field of which, 

 was limited to two small discs separated by a dark space. One of the light spaces 

 was illuminated by rays coming from the zenith, while the other received those 

 from the horizon. " The light from these two regions being partially polarized 

 in directions at right angles to each other, we first ascertained the azimuth under 

 which the two discs presented the greatest difference in illumination, and then 

 bringing its extraordinary ray in contact with the ordinary ray of the least illu- 

 minated region, their light was compared in the manner explained in a former 



