254 Life and Letters of Francis Galton
age is reached? If the State has only a limited amount of money to spend on its children, let it investigate first when it is of most use in improving the breed-whether in infancy, at school age, or during the rapid development of youth.
The reader may think I have given too much space to an ephemeral newspaper article. It is not because of the suggestions it contains, but rather because it exhibits the cautious statements and the moderate proposals to which Galton gave expression even on a topic about which, as those who knew him well can testify, he felt with almost religious fervour.
During this year (1903) Galton had turned to finger-prints again, and was very busy trying to find a measurable character common to all patterns. He endeavoured to obtain this by what he termed the "interspace "-a diameter drawn across the core (of loops or whorls) so as to be perpendicular to both its upper and lower borders. The interspace was to be measured in a mean ridge interval of the core as unit, this mean ridge interval being obtained as the average of ten ridges taken along the interspace. The arches were a serious difficulty, for Galton concluded that they had no interspace, and they tended to lump up at one end of his frequency distributions. Galton's views are given in the accompanying letters ; they were never published, although for the remainder of his life he occasionally returned to finger-print studies. As they may be suggestive to other workers, I reproduce them.
GRAND HOTEL, NAPLES. March 2, 1903.
DEAR KARL PEARSON, Your card of the 26th came all right yesterday, but the previous one which you mention, in reply to my letter enclosing Bicknell's, had and has miscarried. Hence my eagerness for tidings. You say that subscriptions are falling off--here however you will find one and probably two new subscriptions. I have written to Mr H. to say that I am forwarding his letter to you for reply and that I am ordering his book ... to be forwarded to you also. Please answer to him his quere about the way of remitting his subscription. I know nothing of him.
It is to be regretted that biologists do not welcome Biometrika, but the welcome cannot yet be expected. Would it be possible to give a summary of work done, that must prove useful to biology and which without biometric methods could not have been done 'I We seem to need something of that kind more and more ; something so free from technical language that newspapers could copy it, and their readers could understand and like it. Of course it could only contain cream and be in no way exhaustive, but it ought to be so far mentally digestible by the average biological intelligence as to leave some conviction upon it of the utility of biometry....
As regards the finger-prints I am in a little doubt, being not sure how far my collection of Bengal Criminals may be thought suitable, or even whether they are strictly non-selected. From the comparative absence of transitional patterns I fear that many of these may have been sorted out of the collection, which is one of a few hundred duplicates of some of the main collection of about 6000. They were used to enable Mr Henry (now Assistant-Commissioner at Scotland Yard) to show off the rapidity with which the original of any selected duplicate might be traced. It is possible that his clerks may have avoided troublesome transitional cases sometimes, but Mr Henry seems not to be cognizant of this. At all events I should prefer to work on my own collection, but that, alas, is classified, so I should have to go through the whole of it, 2600 odd in number, if I touched it at all. This would be a very tedious job, for I must not draw outlines on the patterns themselves,-which is easy but might spoil them,but must trace them, which is very troublesome even with the best tracing paper and the best light. Would you however look at the enclosed table and tell me how it strikes you? Perhaps you might even get some one to work out the correlation index.