Heise: Radioactivity of Waters, Northern Luzon 295 



Except that a Schocky- Willis radioscope was used instead of 

 the Spindler-Hoyer electroscope, apparatus and method were 

 essentially the same as those previously described in detail." 

 Because of the great bulk of the Schocky-Willis apparatus and 

 its complete lack of accessories for field work, a smaller brass 

 ionization chamber was constructed in the Bureau of Science. 

 The collecting cans and other necessary field equipment from 

 the Spindler and Hoyer outfit were added before the apparatus 

 was taken into the field. By cutting down the size of the ioniza- 

 tion chamber, the sensitiveness was reduced approximately to 

 40 per cent that of the Spindler and Hoyer electroscope. This 

 lack of sensitiveness, together with the mediocrity of the tele- 

 scope and the difficulty in the field of getting readings with 

 the leaf charged to the same potential, made readings somewhat 

 uncertain and increased the percentage of error. Check deter- 

 minations made it appear probable, however, that the limits of 

 error mentioned previously had not been greatly exceeded. The 

 results obtained may be, therefore, considered reliable, except 

 for waters of low activity, for which the exact value of the 

 emanation content is of minor significance. 



The modified apparatus, as assembled in the field for a deter- 

 mination of radioactivity, is shown in Plate I. 



As before, no attempt was made to determine anything but 

 radium emanation content. The data secured for the radio- 

 activity of the waters of northern Luzon are shown in Table I, 

 the results obtained in 1916 and already reported 5 being in- 

 cluded to enable the presentation of the work as a whole. 

 Table I. — Radioactivity of waters of northern Luzon. 



Location (province, sub- 

 province, and town or 

 district). 



I__ I 1* 



May 31,1916 



MOUNTAIN PROVINCE. 



Amburayan, Tagudin . 



do 



do 



May 24,1917 

 — .do 



do 



do 



Benguet, Ambuklao. 

 do 



jRadium 

 Eleva- \ emana- 

 tion Irp tionper 



■"ovelS^Hter.. 



sea 1< "- U1C - (rrams 



level. RaX 



10-«. 



Meters. °C. 



?i:2 



341 



■10 



j trace 



I 137 

 trace 



Flowing well near ce- 

 metery. 



Flowing well, plaza 



Flowing well near school 



North spring 



; West spring 



May 1, 1916 I Benguet, Baguio J Antimok River spring* . 



a Nonthermal. 



* Waters which, owing to the nature of the source, could not be obtained just as they 

 emerged from the ground, or those which may not have been typical ground waters owing 

 to their derivation from springs believed to be local or temporary. 



(*) 



' Wright and Heise, loc. cit. 



