104 



Table II. 



It will he sei-n tlint the niuouiit tloAviiig in at the tirst division of A B 

 is alout two-thirds the total amount flowing into the entire area, and that 

 this supplies the tlowage for the lirst nine divisions of A D while the 

 tenth division of A D gives out the water from j% the distance A B. If 

 the rock in the area be soluble it is easily seen that the water flowing 

 from this lowest division of A D will be very highly charged with mineral 

 matter, while the remaining two-thirds that flows out above will be very 

 slightly charged. This is more especially evident when the long sweeping 

 paths of the water are considered compared with the very short paths of 

 the ^^■a\evs of the first division of A B. We have this represented graph- 

 ically in Fig. 5, where the lines of flow are drawn for the case where 

 A B = 100 and A D = 10, or a typical artesian area. If A D bo a crovice 

 in the rock it is evident that this place Avill be favorable for the deposition 

 of the mineral salt dissolved in the water since the pressure is released at 

 this point and there is apt to exist some reagent that will cause a precip- 

 itate of the ore. This reagent may exist in the crevice itself or in the 



opposite wall. 



In Fig G the curve has been plotted for the flowage from A D for 

 the case A D = 10 and A B = 100. This does not differ much from the 

 case where A D = 10 and A B = 10. except that the convexity downward 

 is somewhat more pronounced, making the curve less like the tractrix. 



Ten equal divisions were taken along A D and the values of y taken 

 from Table II corresponding to different vahies of f. 



The absorption curve for the case A D = 10 and A B = 100 is given in 

 Fig. 7. Here the scale has Been somewhat changed due to the large 

 value of A B. The distance A B was divided into one hundred equal 

 divisions, while the same vertical scale was used for y as in the preceding 

 cases. The values of y were taken from Table II, being the different 

 values of a in that table. 



The rapid fall of the curve at first and then more gradual fall corre- 

 sponds to the values of a found in Table II and also emphasizes the 

 relative slowness of the motion of the water in the right-hand half of the 

 area A B C D. Fig. 5, as compared with that of the left-hand half. 



The method used in the preceding cases might be extended to areas of 

 different dimensions, but the residts would not differ much from those 

 alreadv stated. 



