S/ahu/ifrs. 



31 



roof they must grow with rapidity to attain such length between the frequent jars. 



The bore is almost never continuous, and while externally they are smooth (with 



a minute crystalline 

 marking), within, a 

 mass of stony cells 

 often nearly occupying 

 the diameter of the 

 tube is presented. As 

 long as these tubes 

 grow downward in the 

 quiet upper region of 

 the cave they hang per- 

 pendicularly, but when 

 they reach farther down 

 the currents of air and 

 steam blow the drop 

 with the deposits aside 

 and the tube becomes 

 distorted: it may even 

 return on itself. Many 

 of the resulting forms 

 are shown on the oppo- 

 site page. This collec- 

 tion was obtained from 

 a low cave in the ilow 

 of i88r near Hilo, and 

 as there were many 

 breaks through the 

 roof the currents of air 

 were strong and irreg- 

 ular. There was no 

 steam, but plenty of 

 moisture when I visited 

 the cave, and there was 

 no active growth. In 



one cave in Kilauea in 1S65 the growth of the stalactite was at about the rate of an 



inch a week, but owing to the varying amount of water or steam the produdlion is quite 



[409] 



PIG. 28. STALAGMITES FROM A CAVE IN KII,AUEA. 



