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POPULAR SCIENCE MONTHLY 



Architectural forms are not confined to the United States, nor to 

 the American continent. The Giant's Causeway in Ireland is a 

 familiar example of what they have in those parts, while under the 

 Arabian sky the conditions resemble those in our arid Southwest, 



Fio. 13.— Potholes in Intermittent Stream Course. 



and there we find many fantastic rain carvings. Among these is the 

 Sphinx of El Guerrah, carved by the rain-sculptor doubtless ex- 

 pressly to furnish answers to our " whys and wherefores " concerning 

 this " wondrous architecture of the world." 



Among the applications proposed for the newly liquefied gases is their 

 use as aids in balloon navigation. An aeronaut having a few bottles of 

 liquefied hydrogen or illuminating gas has the means of increasing the in- 

 flation of his balloon when necessary, and need not fear to waste a little 

 gas when he wishes to diminish its levity. Prof. L. Errera, of Brussels, 

 has suggested an apparatus which he calls the ceinture de natation, or 

 natation belt, by which these objects can be conveniently accomplished. 



