TEE GROWTH OF STALAGMITES AND STALACTITES 119 



CLASSIFICATION OF. STALAGMITES 



TABLE III 



Limits of Factors Affecting Stalagmitic Growth 



Factor 



Drip 



Air circulation . . . . 

 Relative humidity, 



Temperature 



Concentration . . . . 



Upper Limit 



D Five drops per second 



A 500 cu. ft. per minute 



H 100 per cent 



T 90° F. 



C 100 per cent 



Lower Limit 



Ratio 



d One drop per 5 minutes 



a h cu. ft. per minute 



h 2 per cent 



t 50° F. 



c 10 per cent 



1 , 500 to I 



1 , 000 to I 



50 to I 



40 to I 



10 to I 



There are five factors given as affecting the growth of stalag- 

 mites, and each of these factors has been assigned two limits: an 

 upper limit and a lower limit. Starting with the drip, it is seen that 

 there will be two general classes of stalagmites: those with a large 

 drip and those with a small drip. Each of these two classes will 

 be further subdivided into two more classes : a class growing under 

 high air circulation and a class growing under low air circulation. 

 If these four classes are further subdivided according to high and 

 low humidity, high and low temperature, and high and low concen- 

 tration, it will be found that a total of thirty- two classes or types of 

 stalagmites are possible. 



It has been found that the circumference of a stalagmite is 

 increased by fast drip and high humidity, and decreased by high 

 air circulation and high temperature. This may be expressed by 

 the relation : Circumference is proportional to 



/ DXH U 

 VAXT/ 



The f power is used because it is in reaHty the surface or area of the 

 face of the stalagmite that is affected, and this increases as the 

 square of the diameter. 



The rate of vertical growth of a stalagmite is favored by high 

 air circulation, high temperature, high concentration, and to a 

 small extent by a fast drip. The only factor opposing a rapid 

 rate of vertical growth is high humidity. It can then be stated 

 that the vertical growth is proportional to 



AXTXCX(i2-flogD) 

 H 



