The Nature of Sea Water 
There is always a punster on board every ship . . . the 
kind who pulls sadistic practical jokes, gives people the “hot 
foot,’ or asks stupid riddles. I remember one who once asked 
us at mess: “. . . and what is the chief constituent of blue 
ink?” 
“Tannin?” asked the skipper. 
“Nope.” 
“Ferric ferrocyanide?” queried a more learned shipmate. 
“Nope.” 
“Red dye, I suppose.” 
“No, give up?” There was a grumbled assent. 
“Water!” he cried, and fell back in gales of solitary 
laughter. 
The chemical constitution of sea water is very complex, 
containing most of the known chemical elements to greater or 
less degree. But, of course, the chief constituent is just ordi- 
nary water. There are so many different elements and com- 
plex ions present that it is impossible to manufacture perfect 
artificial sea water in the laboratory. Good formulas have 
been developed but artificial water can always be distin- 
guished from the real stuff. 
CHEMISTRY OF SEA WATER 
When sea water evaporates it leaves a whitish residue. 
This is the obvious evidence that there are dissolved sub- 
stances in it. The chemical elements present in the sea are 
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