31(i Life and Letters of Francis Galton 



7, Well Road, Hampstead, N.W. May 26, 1907. 



My dear Francis Galton, I wish the Hampstead dream had been realised and that I 

 could first have run in and spoken to you, instead of having to trust to the written word ! . . . 

 Now to the lecture. I like your opening and your finishing extremely, and your centre I should 

 like also, if I heard you deliver it with the manuscript thrust aside, while you talked to the 

 audience in Froebel fashion. I quite realise your point, that it is possible to make these biometric 

 conceptions part of the average man of culture's ideas. Every word you have written would 

 be telling, if you were teaching the teacher to teach. But I am not certain how far your very 

 condensed five object lessons will be acceptable when you bring them in the Oxford June week 

 to your child, not to your teacher. What you must do later is to expand them into a small 

 primer of biometry. Now what I feel is this, that if you do not attempt to read these elements 

 of a primer from your manuscript, but just talk a bit about them in the middle of your lecture, 

 you will lead your audience to read these parts afterwards in print, while you fascinate it mean- 

 while personally as you have the power to do. That is really my sole criticism — an Oxford 

 June audience is the child and not the teacher. 



These other points involve merely suggestions of slight changes : (i) Surely you have inverted 

 the order of our Huxley Lectures. My lecture was in 1903, but I think yours was two years 

 earlier and not the year after. In fact you put the right date on the top of p. 7. So here you 

 will see, you, not I, led the way ! (ii) Will you think me ungrateful, if I ask you not to praise 

 me quite so much? It is natural that I should feel and speak strongly about your work, because 

 I owe so much to it for method and suggestion, but if you praise me 'tis as you branded your 

 own herring as of peculiar virtue. Please re-read in this sense pp. 2 — 3 and 9. I know you 

 will grasp how much I appreciate all your praise, but others possibly will not see it from the 

 same standpoint, (iii) Would it not be well to free yourself on p. 21 from your unit by measuring 

 your A and B in terms of their standard deviations'! You thus avoid the difficulty which occurs 

 to the mind coming fresh to the subject of the index of correlation* depending on the units 

 used — lbs. weight, inches of stature, etc. — and thus providing no comparable ratio, but one 

 varying with the units. If you agree to measuring in terms of your standard deviations as 

 units, all values of the index of correlation are comparable and lie between — 1 and + 1. All 

 this is, of course, very familiar to you [see, indeed, our pp. 5, 51, and Vol. n, p. 393, but it 

 passed from Galton's mind when preparing his manuscript]. 



You would bring it home to your hearer and save him some difficulty, if you gave a hint 

 that the coefficient of correlation lies arithmetically between and 1, and has only a numerical 

 value, being independent of scales, such as those of weight, length or units of pigment intensity. 



I wish I could come to Oxford to hear and possibly help you. I would if it were July, but 

 I am under rather high pressure, and one of my ears is giving me much trouble and exciting 

 the neck in some way. Affectionately, Karl Pearson. 



I shall hear how the lecture goes, I have no doubt; but I should like to hear when you 

 have a chance how the lecturer gets through the exertion, which is another matter. 



Galton was not fit to speak at Oxford, one of the reasons being the 

 accident referred to in the following letter. The. lecture was read by 

 Mr Arthur Galton. 



42, Rutland Gate, S.W. May 27, 1907. 



My dear Karl Pearson, I have now a bout of ill fortune. Feeling particularly well I 

 went on Friday to Bushey Park and returned a bit tired but nothing more. However a horrid 

 bout of bronchitis came on and on Saturday night 12.30 on getting out of bed I rested in the 

 dark on an insecure table with crockery and tumbled on the floor with such a clatter and bound 

 with the bed-clothing dragged after me. I had not the strength to free myself so there I lay till 

 6.30 when the household stirred and the united strength of three maids got me into bed with 

 a very sharp sciatica. It is possible that I may be fit to go to Oxford on June 5 but I feel 

 practically sure that my lecture must be read for me. 



* I use here the term employed by Galton in his lecture; by 1907 the name "coefficient of 

 correlation " was in general use. 



