TILED ROOFS. 



187 



BEING on the subject of roofs, we will take a few more 

 examples of the roof as anticipated in Nature, 



That parallel fibres, whether animal or vegetable, can throw 

 off rain when properly arranged, has already been shown. 

 Much more is it evident that flat or partly flat plates will have 



WINGS OF BUTTERFLY. 



TILEB OF HOUSES. 



the same effect, if they be arranged so that the joints are 

 " broken/' as masons and bricklayers say, i.e. so that the broad 

 part of the upper row of plates overlaps the junction of two 

 of the plates in the row immediately below it. 



Ox the right hand of the accompanying illustration are 

 given two sketches of a modern roof, one slated and the other 

 tiled. The figures on the left show that this formation has 

 been anticipated by Nature, in the wonderful system of scales 

 which cover the wings of butterflies and moths, and to which 

 nil their brilliancy of colour is owing. In spite of their 

 minute size, most being too small to be distinguished by the 

 unaided eye, they are arranged as regularly as the best work- 

 man could lay the slates or tiles on a roof, and on exactly the 

 same principle. 



The shapes of these scales vary in almost every species, but 

 they are always arranged on the same plan, namely, being 

 placed in successive rows, each overlapping the other. 



In consequence, it is almost impossible to wet a butterfly's 

 wing with water. The insect may be plunged beneath the 

 surface, and the long hairs of the body will be soaked and cling 

 together in a very miserable fashion. But the water rolls off 

 the wings like rain off" a slated roof, and even if a few drops 

 remain on the surface, they can be shaken off, and the wing 

 will be perfectly dry. 



Mostly these scales are flat, but sometimes they are curved. 



