ANTHROPOMETRY 57 



practically the same as the preceding, but is marked by a greater 

 rigidity as well as bluntness of the branches, and a reduction of the 

 scale. The Hrdli6ka compass possesses certain adaptations and needs 

 a special description. Of the three older forms of calipers only one, 

 the standard compass of Mathieu, could be used in measuring the 

 height of the head. This measurement is one of growing importance 

 and various methods as well as instruments have been devised in the 

 past for securing it on the living. One of the easiest of methods, for 

 many years practised by the author, was to introduce the branches 

 of the standard compass into the auditory meatus, bring the scale of 

 the instrument over the bregma, note the spread, determine with 

 the rod of the sliding compass the distance from the bregma to the 

 lower edge of the scale, and by a simple arithmetic procedure, obtain 

 the height of the head. But these older instruments had certain dis- 

 advantages when used for this purpose, which were a somewhat 

 inadequate size of the branches in the cases of large heads, an oblique 

 direction of the terminal parts of the branches, particularly when 

 sufficiently dilated for introduction into the ears, and the facility 

 with which the branches penetrated deeper into the ear than required. 

 To obviate these disadvantages, the writer in 1912 visited MM. Collin 

 in Paris and gave directions for making compasses with slightly larger 

 branches, with the terminal parts horizontal at the spread of 10 cm.; 

 and with a guard on the lower portion of each branch 8 mm. from the 

 point, to regulate the distance of introduction into the meatus. The 

 resulting instrument is but imperceptibly heavier than the older stand- 

 ard compass of Mathieu; it serves with equal facility the same pur- 

 poses; and in addition it is thoroughly well adapted for measuring the 

 height of the head. 



7. The Sliding Compass (Compas glissitre). This instrument is 

 too well known to need special description. Figure (10) shows the 

 compass of Collin, which is almost identical with that of Mathieu 

 and is a well-balanced and most useful instrument. The Martin 

 sliding compass shows slight differences, which appear to be matters 

 of personal choice rather than those of additional usefulness. 



8. Large Sliding Compass. There are several instruments of this 

 nature, some made of wood (Paris, American), others of wood with 

 steel branches (Topinard, Manouvrier), and still others wholly of 

 metal (Martin, Hrdlic'ka). Except the wooden and the author's 

 instrument, they have in common the disadvantage of narrow branches, 

 which in measuring the thorax are liable to be pressed into the inter- 



