Guns of various forms and sizes have been invoked for gunpowder, while gun-cotton has been fired in free air and in the foci of parabolic reflectors.
This substance was then employed to filter the beams of the electric light, and to form foci of invisible rays so intense as to produce almost all the effects obtainable in ordinary fire.
Both of these improvements have been introduced, and, as anticipated, the invisible foci have been thereby rendered more intense.
The earth's orbit is an ellipse, one of thefoci of which is occupied by the sun.
The diameter which being produced passes through the foci of the hyperbola is the transverse axis.
The diameter which passes through the fociof the ellipse is the major axis.
Ralph showed Harry first how the figure could be drawn by a string, with two pins to represent the fociof the ellipse.
The combined length of the two lines drawn from any point on the ellipse to the two foci must always be the same and equal to the length of the major axis.
It seemed natural to assume, that this was exactly the case, in which event each of the two foci of the ellipse would have had a special significance in relation to the movement of the planet.
But outside the central trappean area volcanic foci are numerous, as in Cutch, the Rajhipla Hills and the Lower Narbudda valley.
The vessels met with in the parenchyma of the kidney are always greatly distended, and sometimes they are torn, whence there results the formation of small foci of interstitial hæmorrhage.
In certain cases we find extensive areas of fatty degeneration, or small foci in which the hepatic tissue is absolutely destroyed.
Now take half of the long diameter eE, and from point d with cE for radius mark on ee the two points ff, which are the foci of the ellipse.
There are numerous distinct fociof organic production throughout the earth.
In some parts, bright volcanic matter, besides covering one large patch, radiates out in long streams, which appear studded with subordinate foci of the same kind of energy.
In all these directions contagion made its way; and, doubtless, Constantinople and the harbours of Asia Minor are to be regarded as the foci of infection, whence it radiated to the most distant seaports and islands.
Lodging houses, cheap boarding houses, night shelters, hospitals, jails and prisons, are important factors in the spread and frequently constitute foci of the disease.
Therefore a careful search must be made for mild cases which, though unrecognized, may serve as foci for the spread of the disease.
The relative positions of the object and image when placed at different distances from the lens are exactly the same as the conjugatefoci of light rays as shown in Fig.
The relationship which exists between pairs of points in this manner is termed the conjugate foci of a lens, and though every lens has only one principal focus, yet its conjugatefoci are innumerable.
The following is a simple rule for finding the conjugate foci of a lens, and is useful in obtaining the distance from the lens to the photographic plate and the picture to be copied.
Upper Bengal and the dominions which had been recently wrenched from the King of Oude, were the grand foci of mutiny and rebellion; although Jhansi, Delhi, and Meerut, were also centres of active revolt.
It is called "excentricity" because the foci (not the centre) of an ellipse are regarded as the representatives of the centre of a circle.
He expresses the opinion that "The release of sterilized individuals with feeble inhibitions or anti-social tendencies is the equivalent to the creation of so-many new and virulent foci of venereal diseases and promiscuity.
The most eminent men were irresistibly drawn to one of the great foci of secular and ecclesiastical culture.
The great printing-offices were, in a local sense, too, thefoci of intellectual intercourse.
The Committee were given several individual instances in which such girls had acted as foci of infection; they are easily approached, and facile victims for men.
These lavas seem seldom to have issued from isolatedfoci in the manner of modern eruptions, but rather to have welled up along the lines of rectilineal fissures.
We have pointed out how the foci possess a geometrical significance which no other points enjoy.
In the case of Venus the ellipse is still more nearly a circle, and the two foci of the ellipse are very nearly coincident with the centre of the circle.
Let us suppose that a series of ellipses are drawn, each of which has a greater distance between its foci than the preceding one.
Kepler showed that the sun must be situated in one of the foci of the ellipse in which each planet revolves.
It remains local, in spite of increase in number and importance of the foci of disease, as long as the bacilli have not gained access to the blood stream.
From the localfoci of disease the tubercle process spreads chiefly by three channels: (a) By the lymphatics, affecting particularly the glands.
Since we have now to integrate for the whole illumination at a particular point O due to all the components which have their foci in its neighbourhood, we may conveniently regard O as origin.
Are not Damascus, Bagdad and Grand Cairo of more account as plague-foci than a few villages in the Himalaya or in Kattiwar, even granting that the plague may have been in the latter at an earlier date than we know?
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "foci" in a variety of sentences. We hope that you will now be able to make sentences using this word.
