Sent F. Boas to K. Pearson, 14th April 1897.
14 Apr 1897
Description:

‘Dear Sir,

I have to apologise for not having written to you before this, but my engagements during the past year were such that I had no time at all to devote to subjects of statistics. I have been very anxious to send you the material to which I referred in the summer of 1895, but my cards have been quite inaccessible, and I have not been able to do so. I am sending you now, through the Smithsonian Institution, a package of cards which you may find of value. I beg to ask you to make whatever use you can of the material, and kindly return it to me when you have finished with it. Perhaps the simplest way might be if you will have a copy made of the material on teh cards and return the originals to me.

...

I have studied your third contribution to the theory of evolution with very great interest. It strikes me that the methods which you outline in that paper are of the most fundamental importance for the theory of what I might term “biometry.” For a long time I have been of the opinion that our whole system of anthropometry needs a very thorough revision; and the application of your formulas to a number of problems have corroborated my former view. I hope you will continue these important studies, which are certainly doing more to place the theory of evolution on a firm basis than any thing else I know of.

I am sending you a brief paper in which, rather reluctantly, I have not applied the method of correlation indicated by you. My reason for not doing so has been that in the present form the subject will be more readily intelligible, and I am rather anxious to convince my friends here of the futility of investigations based on the method of percentile grades.

I expect to spend the coming summer on the Pacific coast of this continent, studying the ethnology of certain Indian tribes. I am somewhat in hopes of taking up my anthropometric work more vigorously next winter.

I am, dear Sir,

Yours very truly,

Franz Boas.’

Sent F. Boas to K. Pearson, 14th Oct. 1897.
14 Oct 1897
Description:

‘...

I am engaged in investigating the coefficients of regression on[?] several American types and I think there is clear evidence of a very sudden reduction in the value of the coefficients wherever there is evidence of mixture, so much so that the amount of the coefficient I think may be considered evidence of purity of race. I hope to publish the results of this investigation in the course of this winter. The coefficient of regression is high among Americans as compared to Europeans which agrees with the lesser amount of variability among our types. Wherever two distinct types adjoin there seems to be a sudden decrease in the value of the coefficient in the intermediate area. Judging from the material I collected here, I think it likely that the low coefficient you obtain for [illeg.] is due to the great mixture of types in that city.

Yours very truly,

Franz Boas.’

Sent F. Boas to K. Pearson, 17th June 1902.
17 Jun 1902
Description:

‘My dear Sir,

You probably have heard of the establishment of the Carnegie Institution in Washington. As a member of the Anthropological Committee of the Institution I am preparing a suggestion for the establishment of a bureau of anthropometry, in which statistical calculations can be carried out. If a suggestion of this kind is to be successful, it is necessary that we should be in a position to propose names of people exceptionally fitted to do work of this kind. I have in mind the names of a few young men here in America who I believe could do work of this sort fairly adequately, but none who are pre-eminently fitted for this purpose. It occurred to me that there might perhaps be one among your students who with a particular gift for work of this kind combines the great advantages of your teaching, and I should be very much indebted to you if you could recommend any one to me as exceptionally well fitted to conduct work of this kind. I beg to ask you to consider this question as confidential. You will of course understand that I do not know at all if my suggestion will meet with the approval of the Carnegie Institution.

I am, dear sir,

Yours very sincerely,

Franz Boas.’

Sent F. Boas to K. Pearson, 18th July 1895.
18 Jul 1895
Description:

‘Dear Sir,

... I am very much interested in your investigations and shall be pleased to do all I can to assist in the collection of material. I saw the abstract of your investigation in the Proceedings of the Royal Society my attention being called to it by Mr Galton’s notice in “Nature.” I look forward with much interest to the publication of the full memoir which I understand may be expected soon.

I can assist you in two ways. I am engaged at present in the collection of material for the study of the growth of first born children and of first born children of first born children. For this purpose I am collecting data on stature and fingerreach among students and their parents. I expect to have about 500 records by next spring and I shall be much pleased to let you have a set of copies.

Furthermore I have numerous measurements of Indians. It is very difficult to obtain adult children[?] and their parents. But then I found that certain proportions change very little if any after the 61 year of life so that they are available for the study of the laws of heredity and I am using them for this purpose. The proportion which is best suited for this purpose is that of length & breadth of head of which I have records of at least 200 persons. These records are at present in America and the copying and selection of families entails continuall[?] work, but I may be able to send them to you by next March. I shall certainly try to do so.

I should like very much to send you a copy of my paper on the Half Blood Indians which was published in Popular Science Monthly, of September last year which treads upon the question to which you refer. I found that Half-Blood (White and Indian) exceed both parental [illeg.] and stature while their head measurements are such that a reversion to either parental type takes place, more frequently to the Indian type while a middle type is less frequent than either. I ought to add that both parental types are somewhat modified. Unfortunately I have no copy here. I should also like to send you a copy of my paper on the Growth of Children in which I tried to explain the asymetries [sic] of the curve of growth (Science, New York, Vol. 19. p. 256-258, p. 281-283), but I have no copies. I have found that the theory needs some correction but in the main it is correct.

I shall be most pleased if I could help you in any way in the collection of material and I beg to ask you to commend my revision[?].

Yours very truly

Franz Boas.’

Sent F. Boas to K. Pearson, 26th Feb. 1899.
26 Feb 1899
Description:

‘Dear Professor Pearson,

Your publication on correlation and regression of 1896 has increased my interest in these questions very much, and I have had opportunity to investigate a number of questions from this point of view. You may be aware that the subject of correlation of organs had attracted my attention a number of years ago, but my method of treatment was a very imperfect one.

...

It weems to my mind that, in the case of correlation of organs at least, your theory requires a certain modification. Professor [Hermon Carey] Bumpus of Providence, R.I. pointed out to me, that when the correlation between two organs is slight, there is a tendency for extremes in one organ to be associated with increased variability in other organs. That is to say the reduction of variability in our array is not σ(1-22) but contains a term of the first variable. It seems very plausible that the coefficients x11 x12... (Equation I p. 262) should depend upon the values of y, or in words, that the organization of any individual should depend upon the form of its organs. This would necessitate the introduction of numbers of higher orders in the equations.

By the application of the method outlined above, it is easy to give approximations for curves that would comply with these conditions. It seems to me that such conditions can easily be incorporated by comparing the algebraic equations resulting from various assumptions. I will not enter into this subject, but will say a few words on the constancy of the coefficient of correlation in local races. The great differences that you obtained for Janvians[?], Egyptians, etc. in the case of the cephalic index is very puzzling to me. I have, since a long time, suspected that these differences are due to the intermarriage of different races. This result has been borne out very well in an investigation on full blood and half blood Indians in such a way, that I find increased correlation wherever the measurements of the component elements differ...

In all these cases it seems necessary to include terms of higher order in the treatment, since the coefficient of correlation depends upon it. This must be expected, if the mixture of races tends to produce regression to parental forms, as is the case in many instances. The anthropometric material that I have been able to investigate suggests that in pure races Galton’s function is constant, but I am far from certain that this is universally true. At the present time, when I find very low or very high values as compared to the more frequent value, I am inclined to suspect mixture.

I have not investigated many cases of heredity, but it would not seem unlikely that similar conditions may prevail. The whole subject is certainly one of the greatest importance and I am certain that your investigation will revolutionize biological methods, once their significance has been recognised.

Yours very truly,

Franz Boas.’

Sent F. Boas to K. Pearson, 9th July 1902.
9 Jul 1902
Description:

‘Dear Professor Pearson,

Many thanks for your kindly note of June 26. The whole matter is still in its initiatory phase, and I do not know at all what the outcome may be. Your suggestions are of great value to me and I shall make use of them in my report.

Yours very sincerely,

Franz Boas.’