XVI CONTENTS. 



Physiology. H. Zwaabdemaker : "On the strength of the reflex-stimuli as weak as 

 possible". 821. 



PLAITPOINT CURVK (On the phenomena which occur when the) meets the three phase 

 line of a dissociating binary compound. 571. 



PLAITPOINT CURVES (On the shape of the) for mixtures of normal substances. 2iid com- 

 munication. 33. 



PLAITPOINT LINE (Properties of the critical line) on the side of the components. 271. 



— (The exact numerical values for the properties of the) on the side of the com- 

 ponents. 289. 



PLAITPOINT LINES (On the course of the spinodal and the) for binary mixtures of 



normal substances. 3r<i communication. 578. 

 PLANT (Thalictrura aquilegifolium, a hydrogen cyanide-yielding). 337. 

 PLANTS (An enumeration of the vascular) known from Surinam, together with their 



distribution and synonymy. 639. 



— (On) which in the natural state have the character of eversporting varieties in 

 the sense of the mutation theory. 798. 



PLÜCKER equivalents (The) of a cyclic point of a twisted curve. 498. 



POL (d. j. iiülshoff). v. Hulshoff Pol (1). J.) 



POLYANDRY of Scalpellum Stearnsi (On the). 659. 



p o s T M A (o.). Some remarks on the quantity H in Boltzraaiin's "Vorlesungen iiber 

 Gastheorie." 630. 



PRESSURE (Improvement to the open mercury manometer of reduced height with trans- 

 ference of) by means of compressed gas. 75. 



— (Improvement in the transference of) by compressed gas especially for the deter- 

 mination of isothermals. 76. 



— (The Tx-equilibria of solid and fluid phases for variable values of the). 193. 



— of sound (On the) in (;orti's organ. 00. 



PRIMATES (On the relation between the teeth-formulas of the platyrrhine and catarrhine). 781. 

 PRISMATIC CAMERA (The). 605. 

 PROBABILITY PROBLEM (A local). 341. 



PROTEID (On the diflerentiation of fluids of the body, containing). 628. 



p u L L E (a. a.). An enumeration of the vasculnr plants known from Surinam, together 



with their distribution and synonymy. 639. 

 QUADRATIC SURFACES (A particular series of) with eight common points and eight 



common tangential planes. 754. 

 QUANTITY H (Some remarks on the) in Boltzmann's "Vorlesungen über Gastheorie." 630. 

 QUARTZ WIRE (Mass and tension of the) and resistance to the motion of the string. 210. 

 RADIATING POWER (A new method for determining the rate of decrease of the) from 



the center toward the limb of the solar disk. 668. 

 RADi.ATioN (Measurement of the heat produced by the integral) of the corona and the 



solar disk. 503. 



— of heat (On the) in a system of bodies having a uniform temperature. 401. 

 RATE OF DECREASE (A uew method for determining the) of the radiating power from 



the center toward the limb of the solar disk. 668. 



