INTRODUCTION 



13 



the scale used and the method of reading their values; and while the 

 proper methods for each use, with the various compensations to make the 

 actual distance between the points of the two rods, or the exact height of 

 the single rod, correspond to that indicated on the scale, a brief review 

 of the rules to observe may not come amiss. 



(a) To set up the instrument as an anthropometer. Use all four lengths, 

 so adjusted as to make a continuous scale of two full meters, divided into 

 centimeteis and millimeters. A single cross rod is necessary, and this is 

 to be put into the movable socket, with the point prolonging the lower 

 edge of the rod. The proper reading is indicated by a thin edge of metal, 

 borne near the upper end of the socket on the side of the ascending scale. 



(6) To set up the instrument as a rod compass.- Use the two upper 

 lengths only of the main rod, but employ both cross rods. The upper 

 one of these latter, borne by the fixed socket, should be placed with its 

 point prolonging its lower edge; the lower one, borne by the movable 

 socket, should have the point prolonging its upper edge; that is, the two 

 cross rods, when placed together, should have the two points in contact. 

 Thedescending scale should be used, and the reading is indicated by the 

 flat upper surface of the movable socket. Note that the proper com- 

 pensations are made at the beginning of the scale, where three millimeters 

 are taken off. 



Osteometric Board. The osteometric board is used in taking the 

 length of the long bones of the skeleton, and consists of a flat board, 



FIG. 6. Osteometric board of Broca. 



with an inlaid metric scale, and with a cross piece immovably attached at 

 one end. A second cross piece, held always parallel to the latter, slides 

 back and forth along the main board, and the bone to be measured is 

 shut in between the two. The length is then read off on the scale. 



Tape-measure. For all measurements of girth, and also for certain 

 arcs which present themselves on the surface of the head or skull, the 

 wellknown tape-measure, graded to millimeters, is universally employed. 

 The only question in the matter lies between the steel or the cloth form, 

 and each possesses certain advantages. The steel remains unyielding, 

 and is as good for use after years of employment as at first, while even 

 the best weave of cloth stretches, often after a comparatively brief em- 



