1887] Scientific News. ` 105 
then, is to reproduce the objective stimulation, which shall give 
me an equivalent sensation. The two operations being simulta- 
sensations, involving one brain-centre; the operation is easy and 
the error small. When the expressing sense differs from the 
` receiving sense, heterogeneous sensations must be compared, 
involving two brain-centres,—a difficult operation with a large 
error. The large error seems to be due to a looseness of asso- 
ciation between heterogeneous space-centres ; it is a path of high 
resistance. Why this error is in the direction in which it is, and 
not in the opposite direction, depends on some fundamental rela- 
tion of the senses involved, still to be discovered. For the pres- 
ent the fact that the same objective spacial stimulation has a 
different value for the several space-senses is to be emphasized. 
Our conclusions, then, are (1) that the memory for absolute 
measurements is not quite accurate, the order of accuracy being 
sight, span, motion; (2) that the operation probably consists in 
matching the reproduction with the homogeneous mental recol- 
lection ; (3) that the visual inch is too short, the span- and motion- 
inch too long. These conclusions evidently favor the point of 
view of law C. 
D. Finally, a comparison of the error in reproducing by the 
same and by a different sense leads to the very important conclu- 
sion that the former operation is an accurate and easy one, the 
latter an inaccurate and difficult one. The difficulty manifests 
itself as a feeling of discomforting uncertainty and lack of confi- 
dence in one’s judgments, and a great susceptibility of fatigue. 
The connection between senses seems to be a loose one. 
SCIENTIFIC NEWS. 
Engelmann, of Leipzig, announces a continuation of the well- 
known Bibliotheca Zoologica of Carus and Engelmann, bring- 
ing the work down to 1880. The former work contained a cata- 
ation of the Bibliotheca fills in othe gap between the Anz 
and the Bibliotheca of Carus and Engelmann, and thus prs in 
e hands of zoologists a complete list of works on zoology. 
This continuation will be edited by Dr. Taschenberg, of Halle, 
