CON DEN 1D 8: XII 
Mathematics. Jan pe Vries; “The congruence of the conics situated on the cubic 
surfaces of a pencil”. 264, 
— W. A. Versruys: “The relation between the radius of curvature of a twisted 
curve in a point P of the curve and the radius of curvature in P of the section 
of its developable with its osculating plane in point P”. 277. 
— JAN pe Vries: “A congruence of order two and class two formed by conics”. 311. 
— P. H. Scrovre: “On the equation determining the angles of two poydimensional 
spaces”. 340. 
— J. CARDINAAL: “The locus of the principal axes of a pencil of quadratic 
surfaces”. 341. 
—- W. Kapteyn: “The values of some definite integrals connected with Bessel 
functions”. 375. 
— D. J. Kortewec and D. pr Lance: “Multiple umbilies as singularities of the 
first order of exception on point-general surfaces”. 386. 
— P. H. Scuoute: “The formulae of GuLpiN in polydimensional space”. 487. 
— W. Kapreyn: “On a series of BrsserL functions”, 494. 
— J. CARDINAAL: “The equations by which the locus of the principal axes of a 
pencil of quadratic surfaces is determined”. 532. 
— P. H. Scuoure: “On non-linear systems of spherical spaces touching one 
another’’. 562. 
— Jan DE VRIES: “On a special tetraedal complex”. 572. 
— Jan DE Vries: “On a group of complexes with rational cones of the com- 
plex”. 577. 
— R. Meumxe: “On moments of inertia and moments of an arbitrary order in 
spaces of arbitrary high rank”. 596. 
— Jan DE VRIES: “A group of algebraic complexes of rays’, 627. 
— Jan DE Vries: “On nets of algebraic plane curves’. 631. 
— Jan pe Veres: “On linear systems of algebraic plane curves”. 711. 
— JAN DE Vries: “Some characteristic numbers of an algebraic surface”. 716. 
— K. Bes: “The equation of order nine representing the locus of the principal 
axes of a pencil of quadratic surfaces”, 721. 
MEASUREMENT (On the) of very low temperatures, V. The expansion coefficient of 
Jena- and Thüringer glass between + 16° and — 182°C. 674. VII. Comparison 
of the platinum thermometer with the hydrogen thermometer. 290, VIII, Camparison 
of the resistance of gold wire with that of platinum wire. 300. 
MECHANIsM (The) of the salicylacid synthese. 63. 
MEHMKE (k.). On moments of inertia and moments of an arbitrary order in spaces 
of arbitrary high rank. 596. 
MEILINK (B.). On the measurement of very low temperatures. VII. Comparison 
of the platinum thermometer with the hydrogen thermometer. 290. VIII. Compa- 
rison of the resistance of gold wire with that of platinum wire. 300, 
MELTING (On the) of floating ice. 459. 
METALLIC BODIES (The motion of electrons in). I, 438. II, 585. LIL, 684. 
