66 Prof. J. Mihie — On the Flotation of Icebergs. 
tliat bergs exist at all approximating to tliat of a pinnacle Standing 
upon a base, the depth to which they may extend beloio the surface of 
the water is less than the heiglit we see above, and therefore in many 
cases, wken we see a berg 300 feet above tbe water, we may with 
mucb reason assume tbat its depth beneath tbe surface of the water 
is less than 300 feet. 
The case which I have considered is one which appears to be 
applicable to many icebergs, and, I think, to the generality of them. 
It now remains to see how far such views may be carried, and 
also, for the sake of illustration, to consider the possible conditions 
under which some other forms of ice may be regarded as existing. 
In the paper where the conclusion just referred to was arrived 
at, a cone approximating to a berg of ice was drawn as floating with 
its base downwards. The Eev. 0. Fisher (Geol. Mag., 1876, p. 379) 
has, however, raised the question of the stable equilibrium of such 
a cone, which he thinks would not remain in the position as figured, 
but must turn over. Whether this would or would not be the case 
with the cone in question, I am not prepared to answer. The figure 
is only drawn to illustrate the calculation to which it is appended. 
As a practical illustration, to strengthen these views and to show that 
the cone of ice which I have taken will not float with its base 
downwards, Mr. Fisher takes a tetrakedron out of a set of models 
of crystals, and placing it in water finds that it floats with one of its 
angles downwards. 
This I consider to be an unfair comparison, which no doubt has 
led many casual readers to the belief that a cone will also float with 
its apex downwards, and perhaps, in consequence, that my con- 
clusions, being founded on false assumption, must also of necessity 
be false. Lest readers should be led into misconceptions of this 
sort, it may be well to consider how cones of ice would float. 
First, if we take a slab of ice and place it upon water, we know 
that it will float horizontally. On the middle of this slab we might 
raise a small pinnacle of ice, and the mass would still keep horizontal. 
We might next increase this pinnacle round its sides without increas- 
ing its lieight until we reaohed the edges of our slab, and still we 
may imagine the block we have built up keeping its horizontal 
position. We should liere have a figure approximating to the 
probable shape of an iceberg which has travelled into latitudes like 
those of Newfoundland, — a pinnacle supported on a foot or pedestal. 
Such a form approximates to a cone, and such a cone I believe would 
float, and does float with its base downwards, or in other words, 
from a consideration of this sort, it is evident to us that there are 
certain obtuse cones which would float with their apex upwards. 
Secondly, on the other hand, if I make a very acute or tall cone, it 
would never for a moment be expected to float vertically with its 
base downwards more than a tall stick of ice would be expected to 
retain such a position. Such a cone would, according to ordinary 
expectation and according to all probability, fall on its side and float 
more or less horizontally. It is also equally certain that such a 
cone would not float with its apex downwards, as Mr. Fisker’s ex- 
periment might lead one to think. 
