126 PHILOSOPHICAL TRANSACTIONS. [aNNO I766* 



vier than a few pounds, appended to it with sufficient accuracy. To this was 

 attached a flannel bag, into which the children were put, at first naked; but this 

 he soon found very troublesome. The nurses often wanted time sufficient to 

 assist him, and timid mothers were afraid of their infants catching cold; he was 

 therefore obliged to weigh them with their clothes on, and to subtract a certain 

 quantity from the gross weight of each child, according as it was full, middling, 

 or light clothed. Whatever inaccuracy this may have introduced, as to the real 

 weight of the children, it can but little influence their comparative weights, or 

 the differences between the 2 sexes, which it was the object to ascertain. 



For measuring their head, he made use of a piece of painted or varnished linen 

 tape, divided into inches, halves, and quarters. The varnish has the good effect 

 of preventing the length of such a measure being readily affected by variations 

 in the humidity of the atmosphere, &c. ; and it has little or no elasticity. In 

 this part of the experiment then he could pretend to considerable accuracy. He 

 took first the greatest circumference of the head from the most prominent part 

 of the occiput around over the frontal sinuses; and, 2dly, the transverse dimen- 

 sion from the superior and anterior part of one ear, across the fontanelle, to a 

 similar part of the opposite ear. These dimensions appeared the most likely to 

 afford data for determining the respective sizes of the brain in the different sexes. 

 The result was as follows: 



Twenty males^. 

 f,r • L. Circumference 



^^^§^'- ofheads. 



lbs. &c. 

 . 1492- 



,148 . 



'442- . , 



Exp. 1. 

 Exp. 2. 

 Exp. 3. 

 Totals . 

 Average 7 lb. 5 oz. 7 dr. 14. 



Inches. 



, 282. . 

 ,277.. 

 . 280. , 

 . 839. . 



Dimensions 

 from ear to ear, 



Inches. 



152 



146i 



445| 

 7h 



Weight. 



lbs. &c. 



135 

 132 



6 lb. 11 oz. 6 dr. 



Twenty females. 



Circumference Dimen. from 

 of heads. ear to ear. 



Inches. Inches 



272 143 



272 147 



273 I43i 



817 433| 



72 

 '7 



13|. 



Having found the relative proportions between the sexes to turn out thrice with 

 so much uniformity, and observing them to correspond pretty nearly with some 

 experiments, made for very different purposes by the late Professor Roederer, of 

 Gottingen, he did not think it necessary to prosecute the subject further. 



On the whole, it may be observed, that the difference of weight between the 

 male and female at birth may be rated at about 9 oz., or nearly -^^ part of the 

 original weight. In the circumference of their heads there is a difference of near 

 -L an inch, or about a 28th or 30th part; and the same proportion of a 28th is 

 pretty nearly preserved in the transverse dimension. It is evident, as the bony 

 passage through which infants pass is of a certain determined capacity, that were 

 their heads equally incompressible with those of adults, the difference of half an 

 inch in their size would often prove fatal to them. By the compressibility of 

 their heads, however, in well formed women, this difficulty is by time surmounted. 



