236 
Proceedings of the Boyal Society of Edinburgh. [Sess. 
and mechanically connected to a lever for recording on a smoked surface. 
The paper was placed on the pressure plate and the pressure in writing 
on the paper was recorded by the recording lever. Meumann similarly 
employed a pressure plate, but supported it on an air cushion pneumatically 
connected with a recording tambour. The chief defect of any such arrange- 
ment, apart from the complications introduced into the writing process 
itself, is that variations in pressure on the writing plate may be due to 
variations which have no necessary connection with the writing itself, but 
are the result of more or less accidental changes in the position of the 
hand or wrist relatively to the plate. 
The original form of the apparatus shown (fig. 4), which has now been 
modified in some minor respects, was first described by the writer in the 
Journal of Experimental Pedagogy , March 5, 1913. The essential feature 
of the apparatus is that it records the pressure upon the writing point 
Fig. 4. 
itself by receiving the pressure of the top end of the writing instrument 
on a receiving tambour. To this a holding tube is attached into which 
either pencil or pen is slipped. By means of a guiding tube, which serves 
as a holder, the pressure is kept normal to the surface of the tambour. 
In order to lessen friction, as well as to prevent side movements of the pen 
or pencil, a ring — or sometimes two — is placed inside the guiding tube, and 
this just allows the pen or pencil to move freely up and down. By 
connecting the receiving tambour with a recording tambour we get the 
record of point pressure. It is not yet certain whether a light spiral spring 
inside the receiving tambour, in such position that the writing instrument 
presses against it, is an advantage or not. 
For the two pressure recording instruments the names “Grip Pressure 
Cheirograph ” and “ Point Pressure Cheirograph ” might be suggested. 
Both of them might be found serviceable, not merely in the study of writing 
pressure for the purposes of the science of experimental pedagogy, but in 
the science and practice of medicine for the diagnosis of defects in motor 
co-ordination ; as we have indicated, writing pressure, that is point pressure, 
has already been studied to some extent from this point of view. The 
study of grip pressure might also be expected to throw some light on 
writers’ cramp. 
