182 Pigmentation Survey of School Children in Scotland 
English, Irish, French, German, Danish, Dutch, Belgian, Norwegian and Swedish 
speaking peoples, at least, have all of them certain proportions of the red-haired 
class in their respective populations. It thus appears that in every Northern 
race there is likely to be a certain proportion of the red-haired class. A moderate 
proportion (5 per cent.) is found in Scotland generally, and all one can meantime 
say therefore is that it is a characteristic of one-seventeenth of the population 
of the north-east of Scotland to have red hair ; or that that population, observed 
in early time to have red hair, has a significant excess of that class over the 
general proportion found in the country at the present time. 
III. Relationship hetiueen Gaelic speaking Population and Pigmentation. As 
already indicated, one cannot open a discussion as to the origin, distribution and 
characteristics of the Keltic and non-Keltic portions of the population. Nothing 
germane to this investigation would be solved by it. Authorities differ greatly 
as to the facts. One could by an analysis of the colour characters of the popu- 
lation with respect to surnames. Highland, Lowland and otherwise, throw a 
little light on that portion of the Keltic problem bearing on colour. This has 
already been done by the writer for the populations of Aberdeenshire of 1696 
and 1896*, and he proposes at some future time to table the data now collected 
for the whole of Scotland in a similar way. What can be done, however, is to 
investigate the characters of the Gaelic speaking portion of the population as com- 
pared with the non-Gaelic speaking and greater portion, and note whether they 
are really different or not. Here one is on safe ground. The problem of the ethnic 
descent of the Gaelic speaking and non-Gaelic speaking portions of the popu- 
lation the writer leaves untouched. But he proposes to note whether there is any 
particular association of colour with the Gaelic speaking population. In the 
Report on the Scottish Census of 1901 f, the number of "Gaelic and English" 
speaking persons above three years of age is given for each division of Scotland. 
The percentages of Gaelic and English speaking persons in the eight divisions 
of Scotland can thus be found and compared with the corresponding percentages 
for hair colour and eye colour found from the results of this survey. The corre- 
lation coefficients were determined in the following manner: — Let = deviation 
from mean percentage of the Gaelic speaking population ; = corresponding 
deviation from the mean percentage of children belonging to any colour class ; 
o-j = standard deviation of percentage of the Gaelic speaking population ; o-., 
= standard deviation of the percentage of children belonging to colour class s; 
and iV= number of the divisions into which Scotland is divided; then the corre- 
lation coefficient is : 
and determines the degree of association or correlation between the Gaelic speaking 
population and the colour class s. Taking as an example s=jet black hair, the 
following table (Table XXX.) was formed : — 
* British Association Report, Cambridge, 1904, p. 707. 
t Eleventh Decennial Census of the Population of Scotland ivith Report, Vol. i. Table XV. p. xxviii. 
