SNOW AND ICE 47 



find their way out into the cold sea. We have realised that 

 the sea is too cold to melt the ice, which is carried away by 

 :urrents to lower latitudes, and bears with it the waste of the 

 tnd of its birth. 



With the help of some broken pieces of ice we have made 

 ;ebergs in a pond or in an open dish. Our mimic icebergs have 

 lown us that though ice floats it floats with a great part of its 

 >ulk submerged. Using either the rain-water barrel, or a big 

 dish of water, and pieces of ice of various shapes, we have tried 

 to find out how much of the ice is above and how much below 

 water. By repeated experiments we succeed in showing that 

 about one-tenth is above water, and nine-tenths below water. 

 When the frozen pond melts, we watch the great pieces of ice 

 floating on the surface, and again we notice how much bigger 

 each piece really is than it appears to be as it lies in the 

 water. 



But we remember that real icebergs float not in ponds but 

 in the sea, and we resolve to investigate the question whether ice 

 floats in sea water in the same fashion. If sea water is available 

 the experiment may be made direct. If not, it may be imitated 

 by adding common salt to water in the proportion of three and 

 a half parts by weight to one hundred parts of water. The 

 result is of course not sea water, which contains other salts as 

 well as common salt, but it is a near enough imitation for the 

 purpose. It will be found that the ice will not sink so far in the 

 water containing salt as in fresh water. If possible the same piece 

 of ice should be used for the two experiments, which should be 

 carried out under similar conditions. In the denser salt-containing 

 water about one-ninth of the volume of the ice will rise above 

 the surface, while eight-ninths are sunk below the surface. After 

 such an experiment a picture of an iceberg teaches us more 

 than it did at first, for we know now that, in addition to the ice 

 exposed at the surface, there is a much greater bulk below the 

 water. 



The next point to consider is in regard to the melting of the 

 ice. We think of the icebergs from, for example, the Arctic 

 Ocean, which are carried down past Newfoundland by the cold 

 Labrador current. But as these icebergs pass southward they 



