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NATURE 



[June 25, i; 



Glimpses of Nature. By Andrew Wilson. (London : 



Chatto and Windus, 1891.) 

 Mr. Wilson does not profess to present in this book 

 anything strictly new, or to give a full account of the 

 various subjects with which he deals. Nevertheless, the 

 volume may be of considerable value, for on all the 

 groups of facts in which he is interested he is able to 

 discourse brightly and pleasantly, and many of his short 

 papers are well calculated to excite in the minds of in- 

 telligent readers a desire for more ample knowledge. 

 The papers are reprinted from the Illustrated London 

 News. 



LETTERS TO THE EDITOR. 



\The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Ndlher can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part <?/ Nature, 

 No notice is taken of anonymous coinvnimcations.'\ 



The Fusing and Boiling Points of Compounds. 



I HEREWITH send you the translation of a note just presented 

 for me by M. Berthelot to the Paris Academy, as you may see 

 in the Comptcs rendus. I have added two illustrations and a 

 few words in italics. GusTAVUS Hinrichs. 



St. Louis, May 8. 



Statement of the General Law determining the Ftising and 

 Boiling Points of any Compound under any Pressure, as 

 Simple Function of the Chemical Constitution of the same. 

 By Dr. Gustavus Hinrichs. 



The atomic form of normal lineary compounds, such as the 

 paraffins, alcohols, acids, is very nearly prismatic. Ail other 

 serial compounds may be referred to these, either as isomerics or 



The boiling-point / of a prismatic compound consists of two- 

 distinct functions, namely — 



t ^yx+ }'; (I) 



where 



y\ = '^'iliog « -- logoj) (2) 



and 



ji'o = k.,{\QZ o-t - log af (3) 



The symbols Oj and o.^ represent certain definite values of the 

 atomic weight a of the compound, while k^ and k^ are 

 constants. 



For every value of the atomic weight a greater than 03 the 

 formula (i) is limited to / = jj',, which, according to (2), repre- 

 sents the straight line which I call the logarithmic limit, the 

 ordinate being the boiling-point t, the abscissa x, the logarithm 

 of the atomic weight .v = log a. For values of a less than the 

 above limit o.j, the parabolic ordinate jj'.,, determined by (3), 

 must be added toji, according to (i), in order to obtain the 

 boiling-point. 



Accordingly, the boiling-point curve of any homologous series 

 of prismatic atom-form consists of a parabolic arc (3), tangent 

 to the logarithmic limit (2), at the point determined by a = a.,. 

 The constant k^ determines the inclination of the logarithmic 

 limit, and k.^ may be called the parameter of the parabolic 

 branch. 



All compounds derivable by terminal substitution from normal 

 paraffins have a common logarithmic limit, determined by 

 /•j = 583° 75 and Oj = 7278, the pressure being 760 mm. 

 Every individual homologous series of this great family of com- 

 pounds is completely determined by the special values of the 

 two constants a, and k„. For example, the thirty-five normal 

 paraffins C„H2;'+2 are determined by a„ = 201, and the para- 

 meter k.-, = 200°. For the monamines, the corresponding 

 values are a, = 278, and /', = 225°. I have determined these 

 constants for all the important series. Furthermore, these 

 values are themselves functions of the atom or radical which 

 characterizes the head of the corresponding homologous series — 

 that is, H for the paraffins, H^N for inonomines, d-"c. 



If now the co-ordinate s = log/, where/ is the pressure of 



as substitution products. The boiling and fusing points of these 

 latter are obtained from those of the former according to laws 

 and processes publi-hed by me a'^out twenty years ago, partly in 

 my "Principles of Molecular Mechanics," 1874, and in Notes 

 of the Comptes rendus for 1873 and 1875 ; partly in papers of 

 the Proceedings of the American Association for the Advancement 

 of Science for ii,6i. It remains, therefore, only to show how 

 these fundamental points are determined for prismatic com- 

 pounds- 



NO. I 1 30, VOL. 44] 



the saturated vapours, be laid off on the third rectangular axis- 

 the above given values 1 elong to the plane XY determined by 

 / = 760 mm. For the pressure / = 15 mm. the logarith- 

 mic limit is determined by /C-j = Siy^'O, and Oj = Ii3'8l. 

 It will be noticed that its inchnation towards the X axis is less, 

 and that it intersects the same at a greater distance from the 

 origin. The logarithmic limit surface, generated by the log- 

 arithmic limits for all pressures, is a hyperbolic paraboloid, fully 

 determined by the above two lines for 15 and 760 mm. pressure. 



