306 MODEL OF A BUOY. 



what is it? It is an egg an insect egg laid by a mother 

 gnat, instructed by Nature to commit those eggs to water, and, 

 for their preservation on its surface, to build out of them a 

 raft, or life-boat, such as we have now before us.* 



Not far from this we perceive another buoyant object, 

 which, on looking closely, has somewhat the appearance of a 

 minute fish suspended head downwards in the water. A fish 

 it is not, but a gnat larva, which has lately issued from the 

 egg-built wherry, of which its deserted egg-shell still forms a 

 component part. By what means, what apparatus, is the little 

 swimmer thus supported ? Our pocket magnifier may perhaps 

 disclose the mystery. Ah! here we have it! He has no 

 life-preserver round his body, but from the last ring of it 

 branches off at an angle a short pipe or tube, through which 

 the diver takes in a supply of air. Nor this alone, for being 

 terminated by a sort of funnel composed of oily hairs which 

 repel water, this same tube serves the purpose of a buoy, 

 which, assisted by another of like construction at the end of 

 the tail, suspends the swimmer in the water. To descend, he 

 has only to fold up the hairs of this funnel buoy, retaining at 

 their ends a globule of air, and to re-open them when the 

 fancy takes him to mount again to the water's surface.* 



Let us next turn to that curious piece of floating machinery 

 which is now approaching us. But we see, our friends, you 

 look incredulous. " Machinery !" you exclaim, " why we see 



* See Vignette to " A Life of Buoyancy." 



