180 Dr. E. J. Mills on Melting-point and 



with a satisfactory degree of certainty. From this point of 

 view, nothing can be more obvious than the periodicity of 

 infinite olefines. The differences between consecutive values 

 of 2/ x seem to show that the modulus is not a sub-multiple of 

 the value just assigned. 



13. Since - =n modulus, where n is a whole number and 



7 



easily found by a few trial approximations, we are in a posi- 

 tion to calculate the melting-points of series with greatly in- 

 creased accuracy. Putting /3 = 7 n modulus, and yc = A, the 

 equation becomes 



y + yx (y — ■ n modulus) — h (y — n modulus) = 0, 



by means of which the values of 7, h (and thence c) may be 

 deduced from any pair of experiments. We have thus a ready 

 practical means for correcting, inter se, a given series of melt- 

 ing-points. 



Boilikg-poikt. 



The introductory remarks in (3) and (4) enable us, without 

 preface, to pass on to a consideration of boiling-point. 



14. JEthines. — Three of these bodies, belonging to the even 

 group, admit of seriation. Their equation, calculated from 

 0=6, 8, and 10, is 



59-638(0-4*1) 

 y l + -1919O(0-4-l) ; 



the corresponding boiling-points being 83*04, 133*03, and 

 165'02. When 0= oc, ?/ = 310*78. According to the equa- 

 tion, acetylene would boil at —209-78, 



15. Pyridines. — The equation to the even series, calculated 

 from 0=6, 8, and 10, is 



__ 66-626(0-2-62) 

 y ~~ 1 + -18036 (0- 2-62) ; 



the corresponding boiling-points being 139*91, 181-92, 210*93. 

 When = oc, y = 369*41. 



The odd series, for # = 5, 7, 9, has the equation 



44-241(g-l-42) 

 V 1 + -10327(0- 1-42) ; 



the corresponding boiling-points being 115-63, 156-61, 188 # 10. 

 When 0= oc, y = 428*32. t y 11 = 230° is not in this series. 



16. Normal Paraffins. — The equation for the even series 

 has been calculated from 0=6, 8, 12. 



39-315 (0-3*94) 



y- 



1 + -070753(0-3-94)' 



