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of the Dutch population, taken as a whole. To obtain this, it was 
of course necessary to gather the measurements of the heads of a 
sufficient number of people out of every province, and besides, from 
as many as possible different parts of the province. The result of 
my investigations is, that the data of 9975 male inhabitants of 
Holland are at my disposal, which are divided according to the 
provinces as follows: 
Groningen 290, Friesland 768, Drente 460, Overijsel 467, Noord- 
Holland 1326, Zuid-Holland 1495, Gelderland 1379, Utrecht 430, 
Zeeland 1243, Noord-Brabant 883, Limburg 1243. These numbers, 
though rather different, may be considered sufficient for the stating 
of the provincial averages. 
In the anthropological literature one is used, with reference to 
the head, to restrict oneself to communicating the average value of 
the Index cephalicus of some group of population and the statistic 
of the different values from which the average of the index is derived. 
But, as I said before, the Index cephalicus is a proportionate 
number, and so it does not teach us anything about the absolute 
measurements of the head or skull. Yet I think that the absolute 
dimensions of the head, from an anthropological point of view 
deserve more notice than they do now, because they give, after all, 
an idea of the size of the head, as is the case with the length of 
the body. In fixing the sum of the average length and breadth of 
the head of a certain group of the population, one bas a datum, which 
though insufficient, is approximately a standard for the size of the 
head. And this standard is even more reliable than the contour of 
the head, as, by fixing the latter, the varying thickness of the hair 
is included individually. My opinion is, that the sum of the breadth 
and the length of the heads is a rather reliable datum, to answer 
the question by comparison, whether the heads of the inhabitants 
of the different provinces are about the same size, or whether they 
differ in this respect. | worked out my data in this direction and here 
I give the result of my investigations. 
These results are given on the map, added to this article. Two 
numbers are placed in every province. The number placed in the 
northern part of the province teaches us the average Index cepha- 
licus of the persons measured; the southern cipher denotes the sum 
of the average absolute length and breadth of the heads of these 
persons. So both these numbers are provincial averages. This does 
not apply however to the numbers in the provinces of Noord- and 
Zuid-Holland. The numbers mentioned here only refer to the people 
measured in these provinces, after deduction of those living in 
