METEOROLOGY. 305 



rddiophone, it has been sliown by Maccaluco and Grimaldi that the 

 glass surface itself is the cause of the phenomena and not the interme- 

 diate moist air. 



Although the question whether the aqueous vapor absorbs dark heat 

 rays is now decided in the negative, still many questions remain for the 

 meteorologists with reierence to the absori)tion of the solar rays in tbe 

 atmosphere, especially such new questions as the following : How is it 

 with the absorption of bright rays by the atmospheric vapor ? What is 

 the normal atmospheric absorption, when there is no fluid water sus- 

 pended in the air ? How great is the influence of the vaporfor different 

 atmospheric conditions "? What part is played by carbonic acid gas, 

 aud what by the suspended solid impurities called dust? All these 

 questions await their solution, aud can only then be brought to a satis- 

 factory solution when in some favorable climate simultaneous observa- 

 tions are made like Langley's and Abney's during a long period of time 

 at a summit and base station. Why should not this be a proper work 

 for the new observatory upon Mount Etna with Catania for a correspond- 

 ing station ? 



169. [It is proper here to remark that in view of the probable 

 future importance of this class of observations, and at the sugges- 

 tion of Professor Langley, the region surrounding Mount Whitney in 

 California has been set apart as a public reservation and assigned to 

 the Chief Signal Ofiicer of the Army for his use; it is probable that it 

 will be occupied as a special signal station at some time in the future.] 

 {Z. 0. G. M., XVIII, p. 277.) 



170. The Daily Weather Report of the London Meteorological Office 

 for October 1, 1884, states that observations made by navigators crossing 

 the Atlantic, on the temperature of the ocean surface water between 

 Great Britain and ISTewfoundland, show that during the summer of 1884 

 the ocean temperature in the course of the Gulf Stream was abnormally 

 high, namely, general average of 3° in June aud 1°.5 in July above the 

 normal. {Nature, xxx, p. 545.) 



171. The Hydrographic Office of the United States o^avy publishes 

 monthly charts of ocean currents, ice, wrecks, «&c., showing the latest 

 information, as also the prevalent normal condition. This is a very 

 valuable contribution to both navigators and students of the ocean. 



172. Dr. O. Pettersson, as a part of the report of the Norwegian oSTorth 

 Sea Expedition, investigates the constitution and properties of sea- 

 water and sea-ice. He finds the ice frozen out of sea-water to be not 

 necessarily pure, but a compound of the cryohydrates discovered by 

 Professor Guthrie; the sea- water ice is rich in tlie sulphates, aud the 

 remaining brine richer in chlorides. The latent heat developed by the 

 freezing of sea-water is extraordinarily inferior to that of pure water; 

 the contraction of sea- water ice with heat, as the melting point is being 

 reached, becomes more marked the greater the quantity of salt in the 

 ice. {Nature, xxvii, p. 418.) 



g. Mis. 33 20 



