(2) weight promotes regularity and accuracy;
(3) visual control is effective only for reducing variations of error;
(4) the better trained hand is the more accurate in the records, to a slight extent;
(5) there are evidences of semi-hypnotic or dreamy states in the non-visual series.
COMPOUND MOTIONS
Series of records were taken at 100 mm. and 10 mm. bases for the hands, with what is called compound motion. This consisted in an additional movement of the hand that was not ruling with the pencil, in a similar manner, as regards the amplitude and general character of the motion, but in an opposite direction.
For example, suppose the left hand is ruling a 100 mm. line outward, or to the left; coincident with this movement would be a similar motion of the right hand outward or to the right. The origin of both motions, or the starting-ends of actual and imaginary ruled lines, was optional, it being desired to bring out the effect of such additional motion, as little complicated as possible with restrictions, as to its position or extent. Actually this distance varied from about 10 mm. where both motions were outward to 600 mm. for inward motions.
A comparison of such compound motions with single-hand records shows in general the following:
For 10 cm. lines:
The case for mean errors may be summed up by saying: