502 Scientific Intelligence. 
above described, and the effect again noted; then a further turn 
of 90° was made, and so on. Several series of experiments were 
carried on: in one series of eighty trials the mean deflection when 
the membranes of the two halves of the tube ive parallel was 
6°47, and when perpendicular to i other 5°43, a diminution of 
intensity corresponding to 1671 cent; in aie series the 
results were 1°68 and 1°04, cor sedpondilig ‘toa dintutrtion of 38°] 
per cent. When the tubes were filled with air no deflection was 
observed. 
The author eaten that by the repeated saree from the 
surfaces of the membranes separating the co as and air a 
diminution in n intensity is produced according re the relative posi- 
tions of the branes, analogous e effects produced in the 
method of ment is ingenious and the results possess consid- 
erable interest, the soil seems to demand Soon experiment 
before conclusions can safely drawn. The ndividual trials, 
ced di 
two sets of reflecting surfaces, but it seems probable that this 
may be explained ae some peculiarity i in the mechanical construc- 
tion of the appar 
Assumin sha) tities of the longitudinal vibrations of 
sound to have been absolutely demonstrated, the author goes fur- 
ther and draws conclusions, which are far too sweeping consider- 
ing the nature of t oe eile : that all vibrations in 
extended media, as light, are only longitudinal, and that when 
polarization takes place the vibrations become transversal.—Journ. 
Frank. Institute, 1881. 
II. Ggeotogy AND Naturau Hisrory. 
1. The Zine-ore i ataage of Wiesloch in Baden; by Dr. 
Apo.r Scumipt.* 2 pp. 8vo, with 3 plates. Beidelberg: 1881. 
(Carl Winter). “he deposits of zine-ore, described by Dr. 
Schmidt, are situated near the village of Wiesloch, Baden, rigiee 
74 miles south of Heidelberg. The “ Buntsandstein” which 
a esuatierable development at Heidelberg, dips gently to the 
south, and near Nussloch it disappears from the surface and the 
overiping “ Muschelkalk” takes its place; this forms the rock in 
which the zine deposits occur. e zinc is found as the sulphide, 
sphalerite or zine blende, the carbonate, smithsonite, with hydro- 
zincite in limited quantities. Bhd * phalerite roan is — ssa 4 
over a limited area, is regarded a oldest dep uch 
of it, in the form of shell blende (e Schalecblende,”) Aakers of 
thin wavy layers of cryptocrystalline blende of different colors 
and often alternating with galenite or marcasite; much of it is 
* Die Zinkerz-lagerstatten von Wiesloch, Baden, von Dr. A. ScHMIDT. 
