108 
These numbers are useful to a certain extent to give an approximate 
answer to the question whether on an average the head of some 
part of our population is larger or smaller than that of the 
remaining part. 
The results for the different provinces are laid down in the following 
table. For every province the average greatest length, breadth, and 
the sum of the two values is expressed in millimeters. The data of 
Amsterdam and Rotterdam are left out of consideration, because of 
the fixing of the provincial average, these will be communicated 
separately. 
Province Length Breadth Total 
Groningen 192 | 156 348 
Friesland 190.6 | 153.4 344 
Drenthe 192 | 155.6 347.6 
Overijsel 191.4 155.9 347.3 
N. Holland 190 153.— 343. — 
Z. Holland 191.2 152.3 343.5 
Utrecht 190.3 153.2 343.5 
Gelderland 191.7 154.2 345.9 
Zeeland 190.4 154.— | 344.4 
N. Brabant 189.2 154.2 | 343.4 
Limburg 191.7 154.5 | 346.2 
On comparing the data in the last row, we are struck first by the 
fact that the difference between the highest and lowest value is 
remarkably small. The lowest value was found in Noord-Holland, 
where the sum of the average length and breadth of the head amounts 
to 343 mm., while Groningen with 348 mm. is the highest in the 
series. The largest difference amounts only to 5 mm. This difference 
is so small that one would feel inclined to consider it unimportant. But 
a look at the map convinces us that a certain regularity in the 
differences of the provincial averages cannoi be denied. On comparing 
the data on the map, it is evident, that without any exception, the 
eastern provinces indicate a higher sum-average than the western 
provinces. To say it differently: though the increase is small, it is 
yet unmistakable that in the direction of the eastern frontier of our 
country the heads are larger as far as this size may be expressed 
