454 



NATURE 



\_March 13, 1890 



-age, it would probably be found that a not insignificant propor- 

 tion of those marked as 25 were men who were already older 

 when they came into residence. J. Venn. 



About eighteen months ago a brief memoir of mine — " Head 

 Growth in Students at the University of Cambridge "—read 

 before the Anthropological Institute, was published in Nature 

 (vol. xxxviii. p. IS). T^vt means obtained by Dr. Venn, of 

 the " head-products " of Cambridge students between the ages 

 of nineteen and twenty-five were there thrown into the form 

 of a diagram, and discussed. The head-product, I may agam 

 mention, is the maximum length of the head, x its maximum 

 breadth, x its height above the plane that passes through the 

 following three points : i and 2, the apertures of the ears ; 3, 

 the average of the heights of the lower edges of the two orbits. 

 I drew curves that appeared to me to approximately represent 

 the true average rate of growth, and deduced from them the 

 •following conclusions, in which I have now interpolated a few 

 words in brackets, not because any criticism has been founded 

 on their omission, but merely as a safeguard against the pos- 

 sibility of future misapprehension. 



(i) Although it is pretty well ascertained that in the masses 

 of the population the brain ceases to grow after the age of nine- 

 teen, or even earlier, it is by no means so with University 

 students. 



(2) That men who have obtained high honours have had [on 

 the average] considerably larger brains than others at the age of 

 nineteen. 



(3) That they have [on the average] larger brains than others, 

 but not to the same extent, at the age of twenty-five ; in fact, 

 their predominance is by that time diminished to [about] one- 

 half of what it was. 



(4) Consequently, " high honour " men are presumably, as a 

 class, both more precocious and more gifted throughout than 

 others. We must therefore look upon eminent University suc- 

 cess as [largely due to] a fortunate combination of these two 

 lielpful conditions. 



These conclusions have been latterly questioned by two of 

 your correspondents, partly on the ground of discordance among 

 the data, and partly on that of insufficient accuracy of the indi- 

 vidual observations. To this I replied, that materials had since 

 been accumulating, and that a second batch of observations, 

 about equally numerous with those in the first, were nearly ripe 

 ■for discussion, and that I thought it better to defer discussion 

 until these had been dealt with ; then, their agreement or dis- 

 agreement with the first batch would go a long way towards 

 settling the doubt. 



This second batch of observations has now been discussed by 

 Dr. Venn on exactly the same lines as the first one, and I give 

 the results of both in the annexed diagram. The data from the 



first batch, which formed the basis of the above-mentioned 

 memoir, are here shown by dots with little circles round them ; 

 those from the second batch by crosses. 



To the best of my judgment, the conclusions that were reached 

 before are now confirmed. No person can, 1 think, doubt that 

 the swarm of the A dots, and that of the C dots, are totally 

 distinct in character. I have avoided drawing curves through 

 -either of them, lest by doing so the effect of the marks, when 

 standing alone, should be overpowered, and it might be pre- 

 judiced. In their place, small arrow-heads are placed outside 

 each diagram, to indicate the direction of the stretched thread 

 ithat seemed most justly to represent the general trends of the 



two swarms of dots. Then, for the sake of convenient com- 

 parison, lines corresponding to these threads have been placed 

 on the third diagram. It must, however, be understood that I 

 have supposed the lines to be drawn straight, merely for con- 

 venience. In making my own final conclusions, I should take 

 into account not only what the swarms of dots appear by them- 

 selves to show, but also the strong probability that the rate of 

 head-growth diminishes in each successive year, and I should 

 interpret the true meaning of the dots with that bias in my 

 mind. Francis Galton. 



SOCIETIES AND ACADEMIES. 



London. 



Chemical Society, February 6. —Dr. W.J. Russell, F.R.S., 

 in the chair. — The following papers were read : — Observations 

 on nitrous anhydride and nitric peroxide, by Prof. Ramsay, 

 F.R. S. The author recommends as the best method of pre- 

 paring pure nitrogen peroxide that the deep blue-green liquid, 

 supposed to be a mixture of this oxide with nitrous anhydride, 

 which is obtained by condensing the products of the interaction 

 of arsenious oxide and nitric acid, be added to a solution of 

 nitric anhydride in nitric and phosphoric acids, prepared by 

 adding phosphoric anhydride to well-cooled nitric acid ; after 

 agitating the mixture, the upper layer is decanted and distilled. 

 He assumes that the two oxides interact according to the 

 equation : N0O3 + N^Oj = 2N2O4. The melting-point of the 

 peroxide was found to be 10°' 14, in agreement with Deville and 

 Troost's statement. The depression of the freezing-point caused 

 by one part of chloroform in lOO parts of the peroxide was 

 o'''35, and by one part of chlorobenzene o'''37 ; the molecular 

 depression is therefore 41^ The heat of fusion, W, of the per- 

 oxide, calculated from this number and the observed fusing- 



point, by Van't Hoff's formula W = ^^^2?!^, where T is the 



freezing-point of the solvent in absolute degrees and t the mole- 

 cular depression, is 33 "7 cals. ; a direct determination gave 32 '3 

 cals. To determine the molecular weight of nitrous anhydride, 

 a known quantity of nitric oxide was passed into the peroxide, 

 and the depression of the freezing-point determined. Assuming 

 that an amount of nitrous anhydride equivalent to the nitric 

 oxide was formed, the results gave the values of 80*9, 927, and 

 8 I'D against 74, the value corresponding with the formula N^O^. 

 The author was unsuccessful in freezing nitrous anhydride even 

 at - 90" by means of liquefied nitrous oxide. It was found to 

 be soluble in this liquid, and it was further observed that as 

 evaporation took place nitric oxide gas was given off" together with 

 the nitrous oxide ; it would therefore appear that NjOj is unstable 

 even at the very low temperature at which nitrous oxide is liquid. 

 In the discussion which followed the reading of the paper, Mr. 

 Pickering pointed out, with reference to Prof. Ramsay's deter- 

 mination of the heat of fusion of nitric peroxide, that observations 

 on substances which exercise an appreciable influence on each 

 other cannot safely be used in deducing the heat of fusion. 

 Thus in the case of mixtures of water and sulphuric acid, solu- 

 tions containing 29*5, i8'5, 8'6, I'o, and 0*07 per cent, of acid, 

 gave respectively the values 37*4, 58-3, 79*9, 74-9, and 56-3 as 

 the heat of fusion of water, instead of 79 "6. In reply to Mr, 

 Wynne, who remarked that nitric oxide alone should interact 

 with nitric anhydride in the way attributed to N2O3, Prof. 

 Ramsay stated that he had not examined the action of nitric 

 oxide on nitric anhydride. — Note on the law of the freezing- 

 points of solutions, by Mr. S. U. Pickering. — The action of 

 chromium oxychloride on nitrobenzene, by Messrs. G. G. 

 Henderson and Mr. J. M. Campbell. — Studies on the constitution 

 of the tri-derivatives of naphthalene ; No. i, The constitution 

 of )3-naphthol- and /3-naphthylaminedisulphonic acids R. and G. ; 

 naphthalenemetadisulphonic acid, by Prof. H. E, Armstrong, 

 F.R.S,, and Mr, W. P. Wynne. After alluding to the great 

 theoretical importance of a study of the tri-derivatives of naphtha- 

 lene, the authors draw attention to the necessity of determining 

 the constitution of those tri-derivatives which are employed 

 technically in the manufacture of azo-dyes in order that the 

 dependence of colour and tinctorial properties on structure may 

 be determined ; and especially is this the case, since all are not 

 equally valuable — )3-naphtholdisulphonic acid G. (Gelb), like 

 Bayer's ^-naphtholmonosulphonic acid, interacting but slowly 



