44 
NATURE NOTES 
This results from pressure alone, for any comparatively soft 
material, even wax, if kept in ice, can be made to split into flat 
plates at right angles to the direction of the pressure. Flaky 
pie-crust exhibits a similar phenomenon. The interpretation 
is a simple one. If, as an illustration, we place a board on 
a heap of stones of all shapes, and then press down upon it, 
the pebbles will all lie in one plane with their long axes in 
that plane. So if it be imagined that clay is composed of 
unequal-sized particles, these, too, will arrange themselves in a 
similar manner. Hence when the slate rock is split, it will 
obviously do so along the planes or lines of cleavage. 
When a thin slice of slate is examined under the microscope 
the particles are actually seen to be thus arranged exactly in 
accordance with this theory first proposed by the late Professor 
Tyndall. 
There are several kinds of clay in its original soft condition, 
alt of which are compounds of the metal aluminium with oxygen, 
called alumina, mixed with silica, iron, and other matters. They 
furnish several uses. Thus, when granite is decomposed, one of 
its ingredients, felspar, gives rise to a soft unctuous clay called 
kaolin, as at the old tin mines of St. Austell, in Cornwall. This 
is used for china. Potter’s clay is another variety, so also is 
pipe-clay. Ferruginous clay, that is, clay containing iron in the 
form of rust, is common brick earth, which makes red bricks ; 
but if the iron is united with silica it makes white bricks. 
The basis of clay, alumina, is known as one of the hardest 
of minerals — indeed, it comes next to the diamond. Corundum 
and emery are forms of it, as also the precious stones sapphire 
and oriental ruby. 
George Henslow. 
A NATURE RAMBLE IN MALABAR. 
PERHAPS your readers may be interested to hear of 
some of the glimpses of animal life to be witnessed 
during a stroll on the banks of a river in this part of 
the world. It is scarcely correct to call it a stroll, 
however, as the bamboo is so dense (except here and there a 
stretch of about a hundred yards or so) that strolling is out of 
the question, and a scramble is nearer the mark. 
The river in question is the “ Cubbany ” which rises in the 
Western Ghauts and flows within a distance of three miles of 
this bungalow. Let them imagine themselves on the banks (a 
much easier mode of travel than to walk three miles in the 
sweltering heat of the tropics), and watch with me the different 
objects of interest as they appear in their natural haunts. 
But first of all let us get underneath the shade of that wild 
