9 
also slides vertically as well as horizontally, while the fixed 
arm, B C, slides only horizontally ; both arms and their 
carriers are easily removable from the stem, so that either 
one or both may be used as occasion requires. As it is 
often more convenient to work with shorter arms, the curved 
and straight portions are also made as two separate pairs of 
arms instead of the one combined pair here figured. Each 
separate pair of arms fit the carriers. A foot-piece in the 
form of a shallow box, fig. 2, G, in which the arms and their 
carriers are packed, is supplied as part of the apparatus. 
By attaching a rest, H (also supplied with the instrument),, 
to the zero end of the stem, it may readily be held in a 
vertical position on the lid of the box. 
To take the first four measurements in the schedule, p. 12, 
place the arms on the first segment of the stem with their 
extremities projecting equally on either side of it, PL I, fig. 1. 
The length and breadth of the head are measured between 
the curved ends of the arms, the dimensions of the nose 
between the straight and pointed ends. To measure the 
projections Nos. 5, 6, 7 and 8 slide the arm B horizontally 
till its curved end is prevented going further by its carrier C, 
PI. II, move the sliding arm D horizontally in the opposite 
direction till the point of the straight end is only just seen 
beyond its carrier E ; adjust the head of the subject to the 
proper position for measurement, and rest the fixed arm on 
the vertex, the pointed end directed towards the back of the 
head, while the stem is vertical and rests against the point 
of the person’s nose ; slide the carrier E and the arm D 
vertically downwards to opposite the root of the nose, and 
finally slide the arm D horizontally forward till its pointed 
end touches the proper spot, b , PL II, at the root of the nose,, 
when the measurement may be read off on the stem. The 
sliding arm D is now moved horizontally from the face, and 
drawn vertically downwards by means of its carrier E till it 
is opposite the mouth, when the arm D is again projected 
horizontally towards the face, then by careful adjustment 
with the two movements of the arm the measurement from 
vertex to mouth, ff, is obtained. The other projections are 
