The +adverb clause+ may express +purpose+.
6. Language was given us that we might say pleasant things to each other.
+Explanation+.—That, introducing a clause of purpose, is a mere conjunction.
7. Spiders have many eyes in order that they may see in many directions at one time.
+Explanation+.—The phrases in order that, so that = that.
8. The ship-canal across the Isthmus of Suez was dug so that European
vessels need not sail around the Cape of Good Hope to reach the Orient.
9. The air draws up vapors from the sea and the land, and retains them
dissolved in itself or suspended in cisterns of clouds, that it may drop
them as rain or dew upon the thirsty earth.
The +adverb clause+ may express +concession+.
10. Although the brain is only one-fortieth of the body, about one-sixth of
the blood is sent to it.
11. Though the atmosphere presses on us with a load of fifteen pounds on
every square inch of surface, still we do not feel its weight.
12. Though thou shouldst bray a fool in a mortar, yet will not his
foolishness depart from him.
13. If the War of the Roses did not utterly destroy English freedom, it
arrested its progress for a hundred years.
+Explanation+.—If here = even if = though.
14. Though many rivers flow into the Mediterranean, they are not sufficient to make up the loss caused by evaporation.