INTRODUCTION 19 



exactly the same length. When this is done the two are brought per- 

 fectly parallel by swinging them against the smaller of the two parallel 

 uprights. The points of the two needles are now in the proper position 

 the one exactly above the other, but are directed differently, for while 

 the point of the upper needle is directed outwards, as the prolongation 

 of the needle itself, that of the lower is carried upon a secondary piece at 

 right angles to the main needle, and is thus directed downwards, so that 

 it may prick the paper placed beneath the apparatus. 



To project a given line (here a knitting needle fastened to the bone 

 to be measured with respect to torsion) the point of the upper needle is 

 placed in contact successively with two points on the needle defining the 

 axis to be projected, while the lower needle records the points bj r making 

 slight punctures in the paper beneath. If any two approximately 

 transverse axes are both projected so that they cross, an angle is formed 

 that can be easily read. 



In using the parallelograph care must be taken that both transverse 

 needles of the instrument are in contact with the smaller upright, and 

 that they are pushed out equally; as otherwise the points would not lie 

 in the same line vertically. This may be made certain by bringing the 

 upper arm so far down towards the other, that the point of its needle 

 coincides with the median axis of the vertical part of the lower needle. 

 The shape of the upper end of this facilitates this comparison. 



Volumes.- — The principal volumes used by the anthropometrist are 

 those of the cranial cavity and the orbit of the eye, the first one of the very 

 earliest, the other one of the latest of anthropometric data to be developed. 

 For the first, the technique for which is to be found elsewhere, the essential 

 apparatus consists of some medium with which to fill the cavity, such as 

 shot, sand, mustard seed, etc., a graduated cylinder in which to measure 

 the medium, and usually some simple mechanical means to insure a 

 uniformity in pressure during the filling and emptying. 



A control skull, either an actual skull, or a receptacle of similar shape. 

 of known capacity, is frequently used at short intervals during the 

 work, to see that the measurements are made with a fair amount of 

 uniformity. 



Weight. — The weight of an object is seldom used in anthropometry 

 except in the case of the entire body. The weight of certain organs in a 

 perfectly fresh condition, as provided during an autopsy, has also been 

 found of some value, especially in the case of the brain; but the weight 

 of bones depends so much upon their condition, especially with regard to 

 water content, that, except where the condition is absolutely the same, as 

 in comparisons of the weight of the different bones of the same skeleton, 

 such are of no especial value. For all such work any form of reliable 

 scales provided with the metric weights is satisfactory, for accurate bodily 

 weight special forms of scales are obtainable, as are used in gymnasiums, 

 hospitals and clinics. To have any anthropometric value the weight of 



