X, A, 3 Smith: Reconnaissance of Mountain Province 



203 



The country rock at both Mainit and Balotoc is andesite. The 

 water bubbles up at boihng temperature from very small fissures. 

 At the former locality the spring is located in the bottom of a 

 gully and gives rise to a small stream, but at Balotoc the water 

 issues from the bank of Tabia Kiver, In the rainy season 

 the water in the river rises above the vents, and all operations 

 have to cease. 



Following are analyses of the two waters made after both had 

 stood sealed for several weeks : 



Table I. — Analyses of waters from hot springs, northern Luzon."- 



[Figures give parts per million.] 



Constituent. 



Silica (Si02) 



Ferric oxide and alumina (R2O3) 



Calcium oxide (CaO) 



Magnesium oxide (MgO) 



Sodium oxide (Na20) 



Potassium oxide (K2O) 



Carbonic acid radical (CO3) 



Sulphuric acid radical (SO4) 



Chlorine (CI) ..- 



Total . 



Mainit. 



2, 147. 9 



Balotoc. 



195.0 



317.5 



88.0 



8.5.0 



127.5 



867.5 



1.1 



7.1 



457.0 



8,688.0 



23.1 



1,579.6 



208.2 

 295.4 





236.1 



752.6 



11.590.0 



23, 370. 8 



' Samples collected by W. D. Smith. Analyses by Dar Juan, chemist. Bureau of Science, 

 Manila. Sp. gr. at 33° C, 1.010. 



From these we note particularly two things : namely, the great 

 difference in the sodium chloride content of the two waters and 

 the apparent discrepancy in the case of the silica. This is 

 explained by the fact that the silica of the Mainit water is 

 deposited at once and almost before it can be bottled. 



It might be asked whether the existence of buried deposits in 

 beds is indicated by these waters. I do not think so, but believe 

 that the action of subterranean waters of some kind on the 

 igneous rocks will account for the presence of these springs. 

 There are, at least, no surface indications of sediments of any 

 kind in the vicinity. 



Sulphur. — About 2 kilometers southeast and perhaps 300 

 meters above and across the river from the Balotoc springs are 

 eight large steam vents from which copious sulphur fumes issue, 

 and deposited about these are several hundred tons of sulphur. 

 It is said that the insurgents had planned a powder factory 

 here during the late insurrection, but it is evident that they 

 did nothing more than talk about it. This sulphur in its 

 present location has no commercial value. There are likewise 



