EFFECTS OF BAIN. 339 



Q. Why does a SPONGE SWELL when it is 



WETTED ? 



A. Because the water penetrates the 

 pores of the sponge, and drives the 

 particles of the sponge further from each 

 other ; in consequence of which, the bulk 

 of the sponge is greatly increased. 



Q. Wliy do TivDLE-strings SNAP in WET 

 weather ? 



A. Because the moisture of the air 

 (penetrating the string) causes it to swell; 

 and (as the cord thickens) its tension is 

 increased, and the string snaps. 



Q. Why does PAPER PUCKER when it is 



WETTED ? 



A. Because the moisture (penetrating 



_ \ L O 



the paper) drives its particles further 

 apart ; and (as the moisture is absorbed 

 unequally by the paper) some parts are 

 more enlarged than others; in conse- 

 quence of which, the paper blisters or 

 puckers. 



Q. Why do the iceather toys called CAPU'CHINS 

 lift the cowl over the figures in wet weather, and 

 remove it in dry ? 



A. The cowl of the capu'chin is 



