] TRANSACTIONS OF THE SECTIONS. 27 
‘first at the ends, showing that part to be the weakest, we might economize the ma- 
_ terial by making the areas of the ends larger than that of the middle, increasing the 
strength from the middle both ways towards the ends. If the areas of the ends be 
to the area in the middle as the strength of a short column is to that of a long one, 
we should haye for a column, whose height was 24 times the breadth, the area of 
the ends and middle as 13,766 to 9595 nearly. This however would make the ends 
somewhat too strong, since the weakness of long columns arises from their flexure, 
and increasing the ends would diminish that flexure. 
Another mode of increasing the strength of the ends would be that of preventing 
flexure by increasing the dimensions of the middle. 
From the experiments, it would appear that the Grecian columns, which seldom had 
their length more than about 10 times the diameter, were nearly of the form capable 
of bearing the greatest weight when their shafts were uniform; and that columns, 
tapering from the bottom to the top, were only capable of bearing weights due to 
the smallest part of their section, though the larger end might serve to prevent la- 
teral thrusts. This last remark applies too to the Egyptian columns, the strength 
of the column being only that of the smallest part of the section. 
From the two series of experiments, it appeared that the strength of a short column 
is nearly in proportion to the area of the section, though the strength of the larger 
one is somewhat less than in that proportion. 
CHEMISTRY. 
Experiments on the Spheroidal State of Bodies, and its Application to Steam- 
Boilers, and on the Freezing of Water in red-hot Vessels, By M. Bourieny. 
(d’ Evreux.) 
_ M. Boutigny, who made his communication in the French language, first pro- 
_ eeeded to show that a drop of water projected upon a red-hot plate does not touch it; 
_ but that a repulsive action is exerted between the plate and the fluid, which keeps the 
_ latter in a state of rapid vibration. At a white heat, this repulsion acts with the 
_ greatest energy, whilst at a brown-red heat it ceases and the ordinary process of eva- 
_ poration takes place. The temperature of the water whilst in the spheroidal state is 
found to be only 96°, and this temperature is maiatained so long as the heat of the 
_ plate is kept up. To bring the water to the boiling-point (212°), it is therefore ne- 
} cessary to cool the plate. These phenomena are explained by M. Boutigny on the 
_ supposition that the sphere of water has a perfect reflecting surface, and consequently 
_ that the heat of the incandescent plate is reflected back upon it; and some experi- 
_ ments have been made, which show that this is the case, the plate becoming visibly 
_ redder over those parts on which the vibrating globule played. Several experiments 
were made in proof of this necessary cooling to produce ebullition. The red-hot 
plate, with its spheroidal drop, was removed from the spirit-lamp, and after a minute 
_ or two the water began to boil, and was rapidly dissipated in steam. Ammonia and 
_ wether were shown, although so exceedingly volatile, to act in the same manner; the 
_ ether, however, being decomposed whilst in the vibratory condition, in the same man- 
_ neras it is by the action of platina wire, forming a peculiar acid. Iodine put upon the 
heated plate became fluid, and revolved in the same manner as other fluids, no vapours 
_ escaping whilst the high temperature of the metal was maintained; but when allowed 
to cool to the point of dull redness, it was immediately dissipated in violet vapours. 
_ The nitrate of ammonia, when fused on the glowing hot plate, vibrated with great energy; 
_ but on cooling the capsule, the salt entered into vivid combustion. The repulsive 
_ action was shown by plunging a lump of silver at a glowing red heat into a glass of 
_ water. As long as its bright redness was maintained, there was no ebullition; but as. 
; ‘it slowly cooled, boiling tock place. In this experiment, it appeared as if the glow- 
ing metal formed around itself an atmosphere; and the contiguous surfaces of the 
