138 Our IhRi) I'RiEXDs. 



are Moatiiii;- rather than flying ijjarliincs ; tliey are 

 uiaiutained simply by iin[)risoncd gas, and have no 

 pi-()[)ulsive energy whatever. Even soaring contriv- 

 ances on the prijici])le of a boy's kite have proved 

 hi''hl\- (hffienlt and (hin<j'erous to those couraii'eons 

 enongh to entrust their hves to llicni at any 

 elevation. 



Of tlie three elements, earth, wati-r. and air, the 

 last is obviously the most dittieult ti'avelling mediunr 

 A loeomotive engine rests o;i rails laid upon the sur- 

 face of the earth, and a tug-b(»at floats on the water, 

 and both ai-e driven forward by ibr power of steam : 

 but in tlic case of ilight. pnuci- is ]i(c(h'd to lift the 

 machine off iIk- ground and niaiulaiu ii in space as 

 Well as to (li-i\-e ii ouwai'd in an\' desiird dii-iciiou. 

 A little consideration (»t tins xcry iuiportaiU (a<'t 

 will convince anyone that ibe tliglit ot' a i'ird is 

 indeed a wonderfid performance. 



It has been well said that a bird's wing is 

 much hai'der to understand tlian a railway engine 

 or a watch, and some ot the greatest thiidNcrs of 

 modern limes have described it as "a higliK' 

 com[)le.\ apparatus." and 'an i'X(|uisite and com- 

 plicated structure.' 



Feathers and tlighl co\cr a field sutlieieutly wide 

 to tuniish interesting matter foi' a wliole volume, 

 and it is therefore obvious tliat I can <iul\- describe 

 and illustrate a lew such wonders as 1 think will be 

 calculated to set my readers observing and ihiid^iiiL!' 

 for themselves. 



