Consequently when the insect dives, an air-bubble forms around it, a supply of oxygen is thus secured for breathing and the water is kept away from the spiracles.
The new ice had formed around and under the bubble, so that it was included between the two ices.
The stoic offer made laughter bubble within her.
Similarly, the inertia parallel to Oy and Oz is NW' - 1 B W', B C (b2 +-X, c 2 ab and A +C abc/ZP, Ao For a sphere a=b=c, Ao= Bo=Co =, 'a' = Q = = z, (9) U from (II), (16) so that the effective inertia of a sphere is increased by half the weight of liquid displaced; and in frictionless air or liquid the sphere, of weight W, will describe a parabola with vertical acceleration W - W', g (30) W+ aW Thus a spherical air bubble, in which W/W' is insensible, will begin to rise in water with acceleration 2g.
If now the telescope be directed on the target and this level be brought to the centre of its run, the angle of sight can be read - if afterwards any range ordered is put on the sight and the gun truly layed, this bubble will be found in the centre of its run - so that if thereafter the target becomes obscured the gun can be relayed by elevating till the bubble is in the centre of its run, or at a completely concealed target the angle of sight can, if the range and difference of level are known or can be measured from somewhere near the gun, be put on by means of the micrometer screw, and the gun subsequently layed by putting the range in yards or degrees on the sight drum and elevating or depressing till the bubble is central.
It can be restored by moving the bracket till the bubble of the spirit-level is central, and then clamping it.
3 8 53), which connects it with another verbal root naba, " bubble" or "gush."
11 5, p. 329) the author refers to a glass instrument exhibited by himself many years before, and "consisting of a bubble furnished with a long and slender stem, which was to be put into several liquors, to compare and estimate their specific gravities."
In 1721, during the disturbed state of social relations consequent on the bursting of the South Sea bubble, he published an Essay towards preventing the Ruin of Great Britain, which shows the intense interest he took in practical affairs.
Having by these means condensed as much as I could of the phlogisticated air, I let up some solution of liver of sulphur to absorb the dephlogisticated air; after which only a small bubble of air remained unabsorbed, which certainly was not more than of the bulk of the dephlogisticated air let up into the tube; so that, if there be any part of the dephlogisticated air of our atmosphere which differs from the rest, and cannot be reduced to nitrous acid, we may safely conclude that it is not more than 7a part of the whole."
The Grotte des Chevres has been regarded as an enormous gas-bubble in the lava.
To the same frame is attached a bubble, which should be parallel with the centre line of the verniers.
The level bubble, by which the instrument is brought into a position at right angles to the axis of the earth, is generally placed on the top of the telescope.
Certain flat oval nodules from a decomposed lava (augite-andesite) in Uruguay present a cavity lined with quartz crystals and enclosing liquid (a weak saline solution), with a movable air-bubble, whence they are called "enhydros" or water-stones.
This may consist of a steam injector by means of which air is made to bubble through the liquid, which produces both the required agitation and the heating, and at the same time oxidizes at least part of the sulphides; but this method of agitation causes a great waste of steam and at the same time a further dilution of the liquor.
The reason why two levels are employed is that sometimes crystals are formed by the decomposition of the glass which cause the bubble to stick at different points and so give false readings.
Also it is impossible to make levels that are in every respect perfect, nor even to determine these errors for different lengths of bubble and at different readings with the highest precision.
Mehemet Ali's power in Syria had collapsed like a pricked bubble; and with it had gone for ever the myth of his humane and enlightened rule.
It was further thought that the occupation by Great Britain of the country beyond the Orange River had been a bubble and a farce, in which the Cape colonists were all interested; for that it was to them a great gaming table and out of the reach of the police....
- A soap bubble is simply a small quantity of soap-suds spread out so as to expose a large surface to the air.
The bubble, in fact, has two surfaces, an outer and an inner surface, both exposed to air.
When by means of a tube we blow air into the inside of the bubble we increase its volume and therefore its surface, and at the same time we do work in forcing air into it, and thus increase the energy of the bubble.
That the bubble has energy may be shown by leaving the end of the tube open.
The bubble will contract, forcing the air out, and the current of air blown through the tube may be made to deflect the flame of a candle.
If the bubble is in the form of a sphere of radius r this material surface will have an area S = 41rr 2 (I) If T be the energy corresponding to unit of area of the film the surface-energy of the whole bubble will be ST = 41rr 2 T (2) The increment of this energy corresponding to an increase of the radius from r to r-+dr is therefore TdS = 81rrTdr (3) Now this increase of energy was obtained by forcing in air at a pressure greater than the atmospheric pressure, and thus increasing the volume of the bubble.
The volume of the sphere is V = 3 irr3, and the increment of volume is dV = 4lrr2dr Now if we suppose a quantity of air already at the pressure II+p, the work done in forcing it into the bubble is p dV.
We may conceive this pressure to arise from the tendency which the bubble has to contract, or in other words from the surface-tension of the bubble.
If to increase the area of the surface requires the expenditure or or of work, the surface must resist extension, and if the bubble in contracting can do work, the surface must tend to contract.
Let us measure it in the case of the spherical soap-bubble by considering the stress exerted by one hemisphere of the bubble on the other, across the circumference of a great circle.
9 represent a section through the axis Cc of a soap-bubble in the form of a Non- figure of revolution bounded by two herical circular disks AB and ab, and having sp soap- the meridian section APa.
In the next place, there is the surface-tension acting downwards, but at an angle a with the vertical, across the circular section of the bubble itself, whose circumference is 21ry, and the downward force is therefore 2lryT cos a.
If this axis is so adjusted that in the course of a revolution around it the bubble of the level undergoes no change of position, we know that the axis is truly vertical.
Any slight deviation from verticality is shown by the motion of the bubble during the revolution, which can be measured and allowed for.
The motion of the bubble then measures double the inclination of this imaginary axis, or the deviation of a cylinder on which the level may rest from horizontality.
Its deviation from the vertical line is determined by the motion of the bubble of a spirit-level rigidly attached either to the axis, or to the telescope.
The excitement following on the bursting of the South Sea Bubble (q.v.), and the death or ruin of the leading ministers, brought Sir Robert Walpole to the front (1721).
Usually these cavities contain a liquid (water, a saline solution, carbon dioxide or petroleum) and a movable bubble of gas.
He was still at the head of affairs when the South Sea bubble burst and this led to his political ruin.
Hence the equation of work and energy is p dV = Tds (6) 41rpr 2 dr = 8zrrdrT (7) p = 2T/r (8) This, therefore, is the excess of the pressure of the air within the bubble over that of the external air, and it is due to the action of the inner and outer surfaces of the bubble.
If we make CR=z, and suppose z to vary, the shape of the bubble of course remaining the same, the values of y and of a will change, but the other quantities will be constant.