514 



Life and Letters of Francis Galton 



Sir W. Turner and myself had been referred to the original examiners and the whole matter 

 on receiving their report was discussed by the Senate, who sent all the material to myself and 

 I presume to Sir W. Turner also, asking certaiu questions. (They don't want to hear in reply 

 before October.) I thereupon drafted what I had to say and, on returning to town last night 

 (on the way to Dover), posted it to Sir W. Turner. Half an hour after this was done, your letter 

 arrived ! ! 



About the reaction time idea* ; I send the only account on which I can lay my hand of the 

 pendulum apparatus that I used regularly at South Kensington, and which Groves of 79 (?), 

 Bolsover St made for me. We called it, from its shape, the "A" machine. The jar of sudden 

 stoppage is there prevented by nipping a thread kept parallel to the rod of the pendulum by an 

 elastic band. For your case, I should propose a heavy frame for a compound pendulum. The 

 working part being threads with attached weights, whose periods of oscillation are a little 

 shorter than that of the framework, so that for all the useful 

 part of the oscillating they should never leave the frame. The 

 frame should retard them. The nipping would be either by 

 parallel-rule fashion, one pair of them for each string pushed 

 separately, one pusher to each person, or by a vertical arrange- 

 ment on some simple double-lever, pianoforte-key, plan. I find 

 it most difficult to draw what I mean intelligibly, but it appears 

 to work out quite simply and to require no 



skilled workmanship. You 

 formula for graduations. I 

 have forgotten all about it, 

 except that I got hold of 

 some useful tables of Elliptic 

 Functions to calculate them 

 by. Please let me have my 

 printed paper back as I have 

 hardly any copies left. 



I am writing at a strange 

 Athenaeum is in the builders' 

 of the Royal Commission on 

 a Report for Dover. Also I 

 very simple but ratherpretty 

 It was only sent in three or 



will know the 



'-/ b. rod fo - 



push, uifk 



club, to which we are handed over while the 

 hands. When I go home I will send you a copy 

 Horsebreeding Report, on which I have written 

 have (probably) a little probability paper there, 

 and which (I think) may be practically useful, 

 four days ago, and may be crowded out. 

 I heartily hope you are strong and well again. I have been first for three weeks at Royat 

 in France and then for two weeks in Switzerland, which were marvellously health giving. 



Yours very sincerely, Francis Galton. 



42, Rutland Gate, S.W. October 22, 1899. 



Dear Professor Karl Pearson, I cannot suggest anything useful in respect to your paper 

 (which I return), though if you were about to write afresh I should have been inclined to wish 

 the "Logic of Chance " could be more developed. What a difficult subject it is to treat other- 

 wise than technically ! As to the forthcoming lecture at Leeds, let me suggest a diagram f such 

 as the enclosed (see both sides of the paper). It would take people from abstractions down to 

 realities. Also the topic of " nearness of relationship " would interest everybody. To show it off, 

 the string might end in a little longish bag or bucket, into which the tip of the pointer could be 

 slipped. You could then work the string high above your head and all the audience would see 

 it. You will have a very intelligent audience at Leeds, judging from what I saw there some 

 time ago. Very sincerely, Francis Galton. 



* See our Vol. II, pp. 219-220. We have one of Galton's old Reaction Time pendula in the 

 Galton Laboratory, wbich I purchased since his death from an instrument maker. 

 f A very rough model of a genometer : see Vol. m A , p. 30 and Plate I. 



