May 8, 1873) 
NATURE 
23 
One of the important features in this book is the 
frequent graphic delineation of meteorological data. Take 
for example the representation of the decreasing rainfall 
in passing from tropical to polar regions. 
In a similar manner is shown the increase of rain, 
according to altitude, but in this there is evidently a 
mistake in one of the figures. Following this woodcut is 
the representation of the comparative depths of rainfall at 
noticeable spots. 
at the mountain station of Cherra-Poejen in India, where 
upwards of 50 feet of rain annually descend during the 
seven months of the rainy season. 
The engravings of different forms of hailstones are 
Towering over the whole is the rainfall | 
| is here represented on an enlarged scale. 
interesting. Here aresome that fell on different occasions 
At the four corners are represented hailstones that fel 
at Auxerre, on July 29, 1871. The small drawings are o 
the more usual form of hailstones. The two stones in the 
centre are taken from drawings exhibited to the Academy 
of Sciences at St. Petersburgh, in September 1863, 
These stones were ellipsoidal in shape; their surface 
when examined through a lens “had the aspect of six- 
fronted pyramids, and a section of the interior revealed 
| the existence of a hexagonal network of meshes,” which 
The fact of the 
crystalline structure of ice palpably occurring in hail- 
stones, is a most interesting observation, Mere pressure 
lic, 
of adjacent hailstones, like the pressure of soap-bubbles 
in a dish, would hardly produce such definite and regular 
hexagons, 
As indicative of the labour Mr. Glaisher has bestowed 
on this work, we notice that all measurements are given n 
English equivalents, centigrade degrees are converted to 
Fahrenheit, Paris observations are replaced by data from 
Greenwich, and appropriate condensation and excision 
has reduced by one-half the unwieldy size of the original 
work, 
Notwithstanding this evident care, several blemishes 
2. —D/ffiie..t forms of hail. 
have escaped editorial revision. For example, the ascent 
of sound is given as the explanation of the ease with 
which sounds are heard in a balloon. 
On p. 195 it is stated that “The sun’s rays, after 
having. traversed either the air, a pane of glass, or 
any transparent body, lose the faculty of retreating 
| through the same transparent body to return towards 
celestial space.” No reference is here made to diather- 
mic bodies, such as rock-salt, concerning which this state 
ment is wholly incorrect ; and even as regards the most 
| athermic substances, such as alum or water, a considerable 
