422 
POPULAR SCIENCE REVIEW. 
conclusions : — (1) All bodies, whether dark, or having a power of reflect- 
ing, emit the same calorific or luminous ray, at the same temperature. 
(2) The quantities emitted, at a given temperature, by various bodies, are 
proportional to their emissive or absorbent powers for this particular ray. 
(3) It by no means follows that these rays are sensible to either the eye 
or the thermoscope, at the temperatures at which they are given off*. (4) 
Nor is it the case that rays of the same kind emitted by two bodies of 
different absorbent or emissive powers are appreciable at the same tempera- 
ture —See Comptes Rendus , lvii. No. 25. 
Magnetic Storms. — Professor Airy read a paper before the Royal Society, 
at one of its late meetings, upon this subject. In this communication he 
proposes a rather peculiar theory in order to explain the nature of these 
magnetic vibrations. He supposes the phenomena presented by these 
so-called storms to represent the movements of a magnetic ether, which he 
thinks is diffused over the entire surface of the globe, so as to constitute 
an imponderable fluid covering, of several feet in thickness. If then it 
be supposed that this magnetic ether is subject to occasional currents 
produced by some action, or cessation of action, of the sun, which 
currents are liable to interruptions or perversions, of the same kind as 
those in air and water, we have a theory which is quite adequate to the 
explanation of all the singular phenomena which those who have devoted 
themselves to the study of magnetic force are familiar with. 
ZOOLOGY AND COMPARATIVE ANATOMY. 
Development of the Cranium. — The translation of Professor Rathke’s 
essay upon the Development of the Skull is concluded in the January 
number of the Natural History Review. The learned author gives a 
series of results as those deducible from his own observations, of which 
the following are a few : — (1) At the earliest period of foetal life, the 
notochord extends posteriorly to the end of the body, and anteriorly to 
the space between the auditory capsules. (2) The gelatinous mass, which 
at first lies on the sides of the notochord, eventually embraces it, forming 
a sheath, which ends in a point behind, but sends out two processes in 
front. (3) This investing mass is converted into the vertebral column, 
and a great portion, but not all , of the skull. (4) The essential part of a 
vertebra is the body. (5) From the anterior portion of the investing mass 
of the cephalic portion of the notochord are developed the basi-occipital, 
basi-sphenoid, and ethmoid. (6) The basi-occipital constitutes originally, 
like the body of a vertebra, a sheath round a part of the notochord. (7) 
The two sphenoids do not agree perfectly with vertebrae in their develop- 
ment, the anterior diverging more widely from the vertebral type than 
the posterior. (8) Though both sphenoids possess certain characters in 
common with true vertebrae, the ethmoid is differently circumstanced ; it 
never embraces a segment of the nervous tube. It no longer offers any 
special resemblance to a typically-formed vertebra. (9) Thus in regard 
