I 487 ) 



.'{ .-i .'{ 



Iijis Inr (Miiijilioii ill [)(>iiit coordiiialcs 



3 .'i .3 



\{' now «(;/. is llic iiiiiior oC liic (h^lcniiiiiaiil ^'-(-,| J.,,,. I.,,. I 

 (.•on-('s|)()ii(liiin- lo J^y. , tli(> s|»li('i-(' of MoNciK of llic iiidicalcd siiiCacc 

 is i-('|u-esoiite(l In 



l>iil \\(' lia\<' ') ((ii-s=i(ii/:L'^ : so lliis (Mjiialioii can We replaced lt\ 

 S(t (oi- a laiiiiciiliai pencil of' (piadi'atic siii-ra('(>s \\ (» (ind 



3 ■•! 



thai is, the cofrespondini;' spheres of Moncji', (oriii a pencil. 

 To this lieloiiLi,' the poiiit-s[)heres indicated hy 



;? 

 ori;i;iiiatin,u' IVoin twd (Mpnlateral hyperholoids, and the plane d<'lerniine(l 

 hy r/,, -|- />, , >. =r l»elon,n"in,U' to the paraholoid of" the tanuciilial 

 pencil. 



Physics. — " 77/^ r(iri<ihllilii irilh ihf (h'lisllji of llic (jiidnlihi h of 

 till' r(/l/i(//(i/l (>/' sliili'^ l>y ]>r. .1. 1). \ AN DKIv' W A \l,s .In. ( '0111- 

 nmiiical<Ml hy Prof. ,1. j). van dkk AVaai.s. 



§ I. If \V(^ suppose the inolecnles of a pis'-') to he perfeclh 

 smooth, elastic spheres, the iiiflnence of the fact that their dianieler 

 is not inlinitely small, on the form of the (Mpiatioii of stale iiia\ he 

 allo\\('<l for ill lirst approximation hy diininishin,;:- the \(»liinie I^ in 

 ^^ liich the ,uas is c(»iilained, with fonr times the xoliime of the mole- 

 cules. If we iiiid(>rslaiid hy distance sphere a sphere (|(>scril»e(| coii- 

 cejilric with a molecule and with a radius 2 o (where <J denotes the 



1) See inter alia L)Altzi;k, 1. c. \). <J5. 



■•) I say unly "gas" not "gas or liquid", lor \vc iiiiist nol apply llir ruiimil;i 

 for a li<|iii(l willioiil inlrddnciiio- slill oilier apiiroximalcil Irnus llian tlmsc that will 

 be tliscussed here. 



