274 



A. H. PURDUE 



were 95 degrees and 96.5 degrees respectively. Doubtless the 

 temperature is much reduced by the water of the creek and if so 

 it varies with the seasons. The rock layers between which the 

 water issues are quite warm to the touch beneath the surface of 

 the stream. From a rough determination, the flow of each spring 

 was calculated as 5 gallons per minute. A small bathhouse has 

 been improvised, into which water from the south spring is pumped 

 by hand. 



A sample of the water from each spring was taken by the writer 

 and sent to Dr. W. M. Bruce, chemist of the Arkansas Experi- 

 ment Station at Fayetteville, for analyses. These analyses and 

 the average analysis of seven of the springs at Hot Springs are 

 recalculated arid the results given in the following table : 



Constituents . 



Si0 2 



Fe 2 3 +Al 2 3 . 

 K 



Na 



Ca 



Mg 



Fe 



CI 



C0 3 



S0 4 



Total 



Free C0 2 



Grains per U.S. 

 Ion 



gal- 



Caddo Gap Thermal Springs 



South Spring 



Parts per 100,000* 

 1 . 5600 

 o . 7000 

 o . 0000 

 o. 7526 

 3.8876 

 o. 2166 



0.4848 

 6.826s 



o. 1419 



14.5700 



2 . OOOO 

 8.44 



North Spring 



Parts per 1 00,000 ? 

 1.8700 

 o. 7200 



O . OOOO 



°-3349 

 4. 1680 



0.4235 



0.7138 

 6.7085 

 0.2313 

 15.1700 

 1 . 6000 



8.79 



Average of Seven 



Springs at Hot 



Springs 



Parts per ioo,ooof 

 4-445o 



1934 

 4421 

 937o 

 5621 

 0317 

 2819 

 8034 

 7689 

 4655 



11 . 



* Recalculated from analyses by Dr. W. M. Bruce, who gives the constituents as if in (hypothetical) 

 combination; except SiOj and ALOj+Fe 2 Oj. In the recalculation, results were carried out to the fourth 

 place of decimals in order properly to distribute the constituents. 



t Recalculated from data given in Ann. Rep., Geol. Surv. of Ark. (1891), I, 19, where constituents 

 are hypothetically combined, and are stated in grains per U.S. gallon. , 



The similarity of the analyses is striking, but this would be 

 expected in water flowing through the same formations, as these 

 do. It will be noticed, however, that the water of the springs at 

 Caddo Gap somewhat excels in purity the springs at Hot Springs, 

 which are themselves very pure. 



To the geologist, of course, the interesting thing in connection 



