192 ANNUAL OF SCIENTIFIC DISCOVERY. 



Dr. Gould alluded to the ordinary method of freezing ice together by mere 

 juxtaposition. It was his fortune to have a friend who was particularly fond 

 on warm days of refreshing himself with a very highly iced beverage in 

 which the ice was present in very small pieces compounded in various ways, 

 and sometimes eaten with a spoon, though that was not the ordinary method. 

 His experience was that pieces of ice frequently adhered to the spoon and 

 that too although the mixture was not one of pure water but sometimes an 

 alcoholic one. 



Mr. Hill suggested that the phenomenon alluded to by Professor Henry and 

 Dr. Gould was due to crystallization. "With regard to ice going down below 

 the freezing point he had the testimony of scientific witnesses to the fact that 

 ice gathered in Tennessee would not keep so long as that gathered in New 

 Hampshire and Massachusetts. 



Professor Henry said that the fact presented by Dr. Gould was also referred 

 to him by the same gentleman, who was also a friend of his. He repeated the 

 experiment. [Laughter.] To produce a perfect experiment it was necessary 

 that all the conditions should be observed. [Renewed Laughter.] He must 

 therefore give them: Sugar and wine and water were mingled with ice, but 

 instead of depending upon the taste he introduced a thermometer, and 

 observed a reduction. With strong alcohol he obtained a still greater reduc- 

 tion, showing that alcohol has so great an affinity for water that it melts the 

 ice that this is a freezing mixture. 



Professor Agassiz explained the different kinds of ice. First was that pro- 

 duced by the freezing of the surface of the water and successive layers of water 

 beneath it, a laminated schistose mass. Into this, bubbles from the bottom 

 of the pond were frequently frozen, and when it was subjected to the action 

 of the sun the bubbles became heated, melted the ice around them and ren- 

 dered it of no marketable value. It would therefore be worth while for ice 

 gatherers to cover their ponds with cloths, or something which would prevent 

 these bubbles from rising. Glacier ice was formed like pudding-stone ; com- 

 pact masses being cemented together so that when you exposed a large lump 

 of glacier ice to the heat of the sun it would crumble in pieces. It was like 

 the decomposition of conglomerate; we had ice-sand. Icebergs could be 

 determined to be derived from glaciers and not to be the frozen surface of the 

 ocean by their conglomerate composition. Pebbles in glaciers becoming 

 heated melted the ice beneath them and quarried their way down to where 

 the heat of the sun could not reach them. The pot holes formed in this way- 

 were soon covered with a thin film of ice, but it was only during the pro- 

 tracted cold of winter that they were frozen through. 



RESISTANCE OP AIR TO THE FLIGHT OF PROJECTILES. 



The subject of projectiles for the purposes of war naturally excites, at this 

 moment, peculiar interest, and has led to inquiries as to the nature of the re- 

 sistance of the air as the medium through which they move. Air is highly 

 elastic, and, at the level of the ocean, presses uniformly with the force of about 

 15 Ibs. on the square inch of surface. It has been ascertained that air, under 



