NATTTRAL PHILOSOPHY. 163 



Water Soiled in Paper Vessels . Mr. Terrill has laid before the 

 Chemical Society of Paris, facts proving that the paper on wlrch a layer 

 of water is placed, may be heated to the highest temperature without 

 being changed. He states, that the non-eonductibility of the paper for 

 heat, and the constant evaporation of the liquid through the pores of the 

 paper, prevent the combustion of the paper and the ebullition of the 

 water when heated in vessels of paper. During the experiment, thc>re is 

 endosmosis of the exterior gases through the pores of the paper, and 

 hence, when the water contains metallic salts in solution, these are reduced 

 by contact with the flame, after having traversed the paper. 



ON THE PRISMATIC FORMATION OF ICE IN CERTAIN ICE CAVES 



AND GLACIERS. 



A paper on the above subject was read at the last meeting of the 

 British Association by Ilev. G. Browne. These ice caves, he stated, 

 were found in limestone rocks in various parts of France and Switzer- 

 land. The ice was found at depths of from 50 to 200 feet below the sur- 

 face, and at altitudes varying from under 2,000, to nearly 6000 feet above 

 the sea, and appeared in tiie form of columns with spreading b:\ses 

 formed by the freezing of water which dropped from the roof; of ice 

 cascades supported by the sloping walls, and formed by water running into 

 the cave from lateral fissures and in other forms. In many of these 

 caves there was perpetual darkness ; and in almost all of them a candle 

 would burn for hours without giving any sign of the presence of a current 

 of air. In visiting these caves, he was struck by the columnar appearance 

 presented by the fractured side of the ice, and on examining it he found 

 that the whole mass was composed of a vast number of prisms closely com- 

 pacted. He separated the prisms at the edge with the greatest ease, 

 and thrust them out one after the other, as one might thrust out a knot 

 of wood from the edge of a board. The prisms reminded him of the 

 construction of a stone wall, built without mortar, in a slaty country. 

 The irregular stones should form a compact map, and the surface of the 

 walls should be ground smooth. This ice resisted the effect of heat 

 more successfully than ordinary ice. 



ON THE CONDENSATION OF VAPORS ON THE SURFACE OF SOLID 



BODIES. 



A translation of Prof. Magnus's paper on this subject appears in the 

 Philosophical Magazine. Our limited space prevents us giving details 

 of the methods of experimenting beyond the fact that the plate of the 

 substance examined was so placed that, by means of a bellows, dry or 

 moist air could be made to stream upon it, the change of temperature. 

 being determined by means of the thermo-electric pile and a very 

 sensitive needle galvanometer. The Professor in conclusion, asserts, 

 as the results of his investigations, that it has been established that the 

 most various organic and inorganic bodies wax, paraflin, ii'la.-.--, 

 quartz, mica, gypsum, and the most dissimilar salts ; also the morals, 

 whether rough or polished, or even covered with varnish condense 

 on their surface aqueous vapor from the surrounding air, which has 

 the saint' temperature as themselves, and, in consequence of this con- 

 densation, undergo elevation of temperature : and that when the sur- 

 rounding air is changed for air containing less moisture, then a part 



