146 



The Philippine Journal of Science 



urements 5 in the Philippines. The instrument was provided 

 with the usual equipment of tripod, shaking vessel, and cir- 

 culation system necessary for field work (Plate I, fig. 1). 



Fig. 1. A part of northern Luzon. 



Because of the high humidity generally encountered in the 

 Philippines, a small tube of calcium chloride was fastened in- 

 side the leaf chamber of the electroscope. In all determinations, 

 in the field or in the laboratory, a calcium chloride tube (gen- 



5 Wright, J. R., and Smith, O. F., Physik. Zeitschr. (1914), 15, 31-39; 

 This Journal, Sec. A (1914), 9, 51-77; Phys. Rev. (1915), n. s. 5, 459-482; 

 (1916), n. s. 7, 49-61. 



