She shook her head, her focus back on Alex.
Carmen tried to focus on Felipa, but her mind was full of questions.
He forced himself to focus on something else.
She cleared her throat, forcing herself to focus on his dark eyes.
Go see her, keep an open mind, and focus on what is important.
When he could finally focus through the black of the night, he plodded forward, feet wallowing in the soft sand like a boat in a heavy sea.
They hated him because he couldn't focus his magic.
She couldn't focus on anything farther away than her hand, and looking at her hand made her cry.
She stepped into the clammy, wet world of fog and darkness, pausing to focus on the portal that would lead to her sister.s house.
He couldn't focus on the face, but he saw the glowing red eyes.
Her focus right now seemed to be winning Destiny, but Destiny didn't warm to people easily.
Scarcity was the new watchword as the focus turned to all the problems of the future, not all the possibilities.
When nations are young and when they are poor, they usually focus on two things: the military and civil order.
She focused on his eyes as much as she wished to focus on his warm lips.
Try to focus on the damn plate!
One member of Mountain Rescue grabbed him under the arms while another unfastened his line, but he shook off their ministrations while he tried to focus on the activity going on around him.
Her insides quaked, but she breathed deeply to keep calm and focus her mind.
Sofia tried to focus on flipping through a magazine.
"Gabriel, let's not lose focus," Andre said calmly.
If Darian lost his focus and disappeared again, he suspected it'd be another week before he had a chance to sleep.
He shook out his shoulders, trying to focus on whatever it was Kiki had been talking about.
She forced herself to sit on the ground, to focus, to wish with all her heart to go back to Wynn.
Brady's focus returned to his mission.
Before her eyes could focus, pain jolted through her.
I guess because his focus was on Allen.
When she could focus again, she stopped short.
Sam, please focus There are some weird things going on with us and I'm hoping you can help make some sense of them.
Kiera stared at him, struggling to focus on his face when all she wanted to do was study every inch of his perfect body.
Kris said nothing, feeling at once foolish and like he was the child Andre used to chastise for failing to focus on his duties.
She tried to focus on the job at hand.
Allen swallowed audibly, but Giddon shifted his focus to Lisa.
Uneasy, he also realized he had to focus on mopping up the rest of his mess in the mortal world, so he could start to address the underworld.
His focus came back on her.
Xander's face faded in and out of focus, and his thoughts kept drifting away.
"Where's the thermometer?" he asked, his focus still on Destiny.
He despised her video game playing and art, instead saying she needed a man capable of keeping her feet on the ground long enough for her to focus on doing something real with her life.
You must focus on controlling your breathing and keep your eye on the target.
She started with a sketch of A'Ran and found she couldn't focus on anything else.
She shook her head to focus her thoughts.
Now, focus on locating the other three keypads.
Katie picked up the plate, her focus on Carmen.
Well, the diseases that human beings focus on are the ones considered most unbearable.
He saw the woman come into focus, and the man with mossy eyes released him.
Fevered and shivering, she felt too weak and hungry to focus well, but the shape of the black hourglass was unmistakable.
He watched, confirming the far side of the planet wasn't the focus of either Yirkin or Qatwali forces.
This makes business a meritocracy and encourages business owners to focus on quality, service, and reputation since these are so easy for customers to check.
It was a picture taken at the party and the focus was on Carmen and Alex.
She began to steady her breathing and focus, so she could draw a portal when they were gone.
Inexplicable scenes tore through her mind too fast for her to focus on any one of them.
The sounds and smells of the forest nearly caused them to lose focus and stop running to fully experience their surroundings.
They will take advantage of the freedom from financial want that the modern age gives them and will focus on improving themselves and the world they live in.
The initial sensations passed, and he breathed deeply, finally able to focus as his body adjusted to the feel of the energy flowing through him.
Brady brooded then dismissed everything to focus on his surroundings.
With great focus, she dug through the undergarments in the dresser and chose a set that matched, like human-Deidre did.
We will be completely insulated from the collecting and researching of data so that we can focus entirely on turning data into knowledge.
"How?" she managed, needing to focus on something other than him.
I want to be able to focus on solving this problem, not worrying about what might be said or done to you.
"Let's focus on Rhyn," Kris said with barely controlled anger.
She had one focus: to be with you in a way you couldn't be together when she was Death.
As much as he'd loved Lilith, Andre had told him she wasn't meant to be his mate and encouraged him to focus on his duty rather than the woman.
In 259 Odenathus, the Palmyrene adventurer whose memory has been eclipsed by that of his wife Zenobia, laid Nehardea waste for the time being, and in its neighbourhood arose the academy of Pumbedita (Pombeditha) which became a new focus for the intellectual life of Israel in Babylonia.
Let AB be the major axis of the orbit, B the pericentre, F the focus or centre of motion, P the position of the body.
Let the curve represent an elliptic orbit, AB being the major axis, DE the minor axis, and F the focus in which the centre of attraction is situated, which centre we shall call the sun.
Another curious theorem proposed by Bouilland in 1625 as a substitute for Kepler's second law is that the angular motion of the body as measured around the empty focus F' is (approximately) uniform.
Yellow fever (which first appeared in Cuba in 1647) was long the only epidemic disease, Havana being an endemic focus.
Taco bell offers salads, bean burritos, and menu items which focus on beans, rice and tomatoes.
The focus of these dishes is on fresh ingredients that provide a lot of flavor without a lot of calories such as fresh vegetables and herbs.
Some emphasize the food, others place their focus on the fun, with food on the side.
The menu, which changes with the seasons, focus on fresh, local and organic food items.
He couldn't focus and strained against whatever held him in place.
From the surface to 500 fathoms the general form of the isothermals remains the same, except that instead of an equatorial maximum belt there is a focus of maximum temperature off the eastern coast of the United States.
Obviously this writer is harder to focus than Kant or Hegel.
3 Leibnitz's doctrine of continuity necessarily led him in the same direction; and, of the infinite multitude of monads with which he peopled the world, each is supposed to be the focus of an endless process of evolution and involution.
It would shift the focus from Lori to Jonathan and make him feel more welcome.
The court at which he grew up was the focus of great activities, for Philip, by war and diplomacy, was raising Youth.
In 1639 Avranches was the focus of the peasant revolt against the salt-tax, known as the revolt of the Nu-pieds.
Sir David Brewster modified his apparatus by moving the object-box and closing the end of the tube by a lens of short focus which forms images of distant objects at the distance of distinct vision.
The congress of zemstvos, hitherto the focus of Liberalism, had petitioned the government, before the opening of the third Duma, to take measures for the restoration of order.
The spectra of the stars he obtained by using, outside the object-glass of his telescope, a large prism, through which the light passed to be brought to a focus in front of the eye-piece.
focus by two tangents drawn from a point), and (having given the focus and a double ordinate) he uses the focus and directrix to obtain any number of points on a parabola - the first instance on record of the practical use of the directrix.
A really great weblog with a particular focus on London life.
Design: Qualitative focus group study consisting of 11 focus group study consisting of 11 focus groups with 67 participants.
focus on INDIA Welcome to all our Indian collaborators who have joined recently.
focus of attention.
Other focusing options include manual focusing, auto focusing lock, focus bracketing and an auto focus assist beam for lowlight photography.
MORI has already held focus groups at various locations in England and Wales in order to gather views.
The focus on Ireland proved apt given that so much of what has gone on there provides lessons for elsewhere.
"But I'm not done –" Rhyn snatched the open can of food and flung it into the forest. Toby stared at him then took his pink coat and crawled deeper into the little cave. Rhyn stretched out on his back next to the fire, his mind puzzling over the angel's words. However much he tried to focus on what it was Death had agreed to, he couldn't escape his mixed emotions or one errant thought.
Death was right. Kris didn't have what it took to keep the Council together. He may have just lost one of his brothers, because he lost focus of what he should've done. Maybe he should've known Jade was a traitor or Hannah was a demon. He hadn't known of Andre's danger or been able to bring the Council together to fight the demons that threatened them all. He hadn't been able to keep Hannah safe or Toby or Katie.
It was best to focus on the things within her grasp – like Alex.
She blinked, trying to bring it into focus.
For the next two days she tried to focus on the wedding plans.
Only this time her focus spread out to other things; the arbor of forget-me-nots where they would exchange vows, the cake with its three tiers of cascading flowers.
Maybe if she would focus on assisting him in that, it would be less intimidating.
She kept her focus on the task of loading her plate, avoiding his gaze.
By the time children came along, they would be ready to focus on them in unison.
The youth was not too far off: Claire had been all Darian wanted to focus on since he'd met her.
Too weak to focus, she didn't know who it was until he'd knelt beside her.
Find one, focus on him, and let your power do its job, Charles answered.
What you need to focus on is surviving the next two weeks.
But I think your focus should be on the Others.
"What makes you think they won't focus Darian on destroying our world?" she demanded.
Sirian's cool voice broke into his quiet focus.
He met her gaze and held her eyes, forcing her to focus on him.
The man before her gripped her shoulders again and shook her, and the fuzzy faces of the men from her guard came into focus.
Rissa drew a deep breath with difficulty and forced her mind to focus.
As she struggled to focus and keep her tears away, another thought came to her.
Her own breathing was loud in the pause, and she tried to focus on his voice and not the dark thoughts in her mind.
Aaron finally spoke, as his focus shifted from Rob to Carmen.
He tried to focus on the book again, but after a few minutes something compelled him to look at her.
Right now he'd best focus on the job ahead and forget about things like that.
That internal focus had ultimately cost her the ultimate relationship.
They would have enough on their plate for a while, and waiting would assure that they could focus on the baby.
If he kept their attention divided and their focus on their turf wars, he was largely overlooked.
She went to the iPad and tried to focus on reading her rules.
You may want to focus on a headshot.
Jessi's focus returned to Xander.
Jule's focus was on her.
There almost seems to be more to you, she considered, focus on the road.
Her focus was clear: getting her cousin to safety without any sort of consideration for her own welfare.
Xander found himself hesitating before he released his focus on molding his power.
When he lifted his head, her thoughts were too addled for her to focus on anything more than the sensations of the body against hers.
One of the most essential points in a good micrometer is that all the webs shall be so nearly in the same plane as to be well in focus together under the highest powers used, and at the same time absolutely free from " fiddling."
The result is that no trace of " fiddling " exists, and the movable and fixed webs come sharply together in focus with the highest powers.
The scales of the images formed in the focus of the eyepiece common to both microscopes shall be identical.
then the lines of the stellar spectrogram would be seen in focus of the eyepiece and the image of the solar spectrograph would be obliterated.
Below the surface a focus of maximum temperature appears off the coast of South America in about 30 S.
With the rise of Llanelly the industrial importance of Carmarthen has tended to decline; but owing to its central position, its close connexion with the bishops of St David's and its historic past the town is still the chief focus of all social, political and ecclesiastical movements in the three counties of Cardigan, Pembroke and Carmarthen.
Every monastery erected in the Magyar wildernesses was not only a centre of religion, but a focus of civilization.
His two newspapers, the Illyrian National Gazette and the Danica Ilirska (Illyrian Daystar) provided a literary focus for the rising generation; while his reform of Croat orthography, planned on parallel lines with Vuk Karadzic's epochmaking philological work in Serbia, assured to modern SerboCroat literature a definitely unitary development.
The Serbian court, instead of being a centre of perpetual scandal and misrule, resumed its true position as a focus of national aspirations, and this change was not lost upon the Yugosla y s of " the other side."
In the absence of a heliostat it is more convenient to obtain a point of light with the aid of a lens of short focus.
If the origin of light be treated as infinitely small, and be seen in focus, whether with the naked eye or with the aid of a telescope, the whole of the light in the absence of obstacles would be concentrated in the immediate neighbourhood of the focus.
The question is whether, when the adjustment of focus is correct for the central rays of the spectrum, the error of phase for the most extreme rays (which it is necessary to consider) amounts to a quarter of a wave-length.
focus this condition is satisfied if the aperture does not exceed 2 in.
focus might have an aperture of 22 in., and the image would not suffer materially from aberration.
Mag., 1885, 20, P. 354) that a displacement 8f from the true focus i will not sensibly impair definition, provided Sf
A rotation of this amount should therefore be easily visible, but the limits of resolving power are being approached; and the conclusion is independent of the focal length of the mirror, and of the employment of a telescope, provided of course that the reflected image is seen in focus, and that the full width of the mirror is utilized.
If a surface intended to be flat is affected with a slight general curvature, a remedy may be found in an alteration of focus, and the remedy is the less complete as the reflection is more oblique.
The explanation of the difference of focus upon the two sides as due to unequal spacing was verified by Cornu upon gratings purposely constructed with an increasing interval.
Then, if Q be any radiant point and Q' its image (primary focus) in the spherical mirror AP, we have 1 1 2cos4) v l + u 'a ' ' where v 1 = AQ', u =AQ, a =OA, =angle of incidence QAO, equal to the angle of reflection Q'AO.
In order that a large part of the field of view may be in focus at once, it is desirable that the locus of the focused spectrum should be nearly perpendicular to the line of vision.
The mechanical arrangements for maintaining the focus are of great simplicity.
The expression (5) gives the illumination at due to that part of the complete image whose geometrical focus is at =o, the retardation for this component being R.
The secondary pulses diverted by the ruling fall upon an object-glass as usual, and on arrival at the focus constitute a procession equally spaced in time, the interval between consecutive members depending upon the obliquity.
Diffraction when the Source of Light is not seen in Focus.
As a source of light he used sunshine passing through a very small hole perforated in a metal plate, or condensed by a lens of short focus.
Of such are tetanus and diphtheria, now known to be due to the establishment from without of a local microbic infection, from which focus a toxin is diffused to the nervous matter.
Discontent in Ireland was now rapidly becoming dangerous, and was finding a focus in the Society of the United Irishmen, and in the Catholic Committee, an organization formed a few years previously, chiefly under the direction of Lord Kenmare, to watch the interests of the Catholics.
This beautiful street, with its northward branches, Park Lane, from which splendid houses overlook Hyde Park, and Bond Street, lined with handsome shops, may be said to focus the fashionable life of London.
ZUy2BB0 Bll; reducing, when the liquid extends to infinity and B 3 =0, to = xA o' _ - zUy 2B o so that in the relative motion past the body, as when fixed in the current U parallel to xO, A 4)'=ZUx(I+Bo), 4)'= zUy2(I-B o) (6) Changing the origin from the centre to the focus of a prolate spheroid, then putting b 2 =pa, A = A'a, and proceeding to the limit where a = oo, we find for a paraboloid of revolution P B - p (7) B = 2p +A/' Bo p+A y2 i =p+A'- 2x, (8) p+?
Fearing that the little court of the Inca Tupac Amaru -(who had succeeded his brother Sayri Tupac) might become a focus of rebellion, he seized the young prince, and unjustly beheaded the last of the Incas in the square of Cuzco in the year 1571.
He shows how the paper must be moved till it is brought into the focus of the lens, the use of a diaphragm to make the image clearer, and also the application of the method for drawing in true perspective.
When the members of a shower are observed with special regard to their directions it is seen that they diverge from a common focus.
The meteors, whatever their dimensions, must have motions around the sun in obedience to the law of gravitation in the same manner as planets and comets - that is, in conic sections of which the sun is always at one focus.
' In this condition the eye is elongated from before backwards, so that the retina lies behind the principal focus.
All objects, therefore, which lie beyond a certain point (the conjugate focus of the dioptric system of the eye, the far point) are indistinctly seen; rays from them have not the necessary divergence to be focused in the retina, but may obtain it by the interposition of suitable concave lenses.
In hypermetropia the retina is in front of the principal focus of the eye.
The immediate seismic focus appeared to be in the straits, but Dr E.
As an astronomer, Rittenhouse's principal merit is that he introduced in 1786 the use of spider lines in the focus of a transit instrument.
It is usual to place a glass ball on a dark ground, to sit with the back to the light, to focus the gaze on the ball (disregarding reflections, if these cannot be excluded), and to await results.
Initiated from childhood in all the arts of diplomacy at what was then the focus of civilization, and as much a warrior by nature as his imperial kinsman Manuel, Bela showed himself from the first fully equal to all the difficulties of his peculiar position.
But as the orbits are not centred on the sun, which is in a focus of each, the displacement of the seeming circle would be readily seen in the case of Mercury and of Mars.
Thus at the focus two images of the sun were formed nearly in contact as in fig.
Savary dwells on the difficulty both of procuring lenses sufficiently equal in focus and of accurately adjusting and centring them.
Some excellent instruments of the second type were subsequently made by Dollond's eldest son Peter, in which for the " convex glass within the tube " was substituted an achromatic object-glass, and outside that a divided negative achromatic combination of long focus.
focus), Franz von Paula Triesnecker made a series of measurements at the observatory of Vienna which has been reduced by Dr Wilhelm Schur of Strasburg (Nova Acta der Ksl.
focus, would correspond with 2" of arc. But, after all, this is no practical difficulty, for screws can be used to separate the lenses, and, by these screws, as in a Gascoigne micrometer, the separation of the lenses can be measured; or we can have scales for this purpose, read by microscopes, like the Troughton 1 circles of Piazzi or Pond, or those of the Carey circle, with almost any required accuracy.
focus) which have since become historical instruments.
by changing the distance between two object-glasses of equal focus.
The chief objections to the method are that, as one star is in the axis of the telescope and the other displaced from it, the images are not both in focus of the eye-piece,3 and the rays from the two stars do not make the same angle with the optical axis of each segment.
The second method is free from the objection of non-coincidence in focus of the images, but is more troublesome in practice from the necessity for frequent readjustment of the position of the eye-piece.
Thus, in measuring the largest as well as the smallest angles, the images of both stars would be equally symmetrical and equally well in focus.
There is a collar, clamped by the screw at S, which is so adjusted that the eye-piece is in focus when pushed home, in its adapter, to this collar.
Ramsden's dioptric micrometer consists of a divided lens placed in the conjugate focus of the innermost lens of the erecting eye-tube of a terrestrial telescope.
The magnifying power of the eye-piece is that of a single lens of focus = Jp.
It afterwards became the seat of the dukes of Bavaria, and one of the main bulwarks of the East Frankish monarchy; and it was also the focus from which Christianity spread over southern Germany.
It may be regarded as an epicycloid in which the rolling and fixed circles are equal in diameter, as the inverse of a parabola for its focus, or as the caustic produced by the reflection at a spherical surface of rays emanating from a point on the circumference.
He appears soon to have found that single lenses of very short focus were preferable to the compound microscopes then in use; and it is clear from the discoveries he made with these that they must have been of very excellent quality.
The diamond-shaped pointer is always in focus; focusing for individual eyesight is effected by turning the eye-piece, which is furnished with a scale for readjustment.
For instance, a ticking watch may be put at the focus of a large concave metallic mirror, which sends a parallel " beam " of sound to a second concave mirror facing the first.
If an ear-trumpet is placed at the focus of the second mirror the ticking may be heard easily, though it is quite inaudible by direct waves.
Or it may be revealed by placing a sensitive flame of the kind described below with its nozzle at the focus.
As light is concentrated into a focus by a.
The amount of precipitation is greater in the north-west and on the mountains, because in the one case the mountains of lower elevation are a less obstruction to the moisturebearing winds from the west, and in the other the mountains condense the moisture; the mountains which stand in isolated groups upon the plains are frequently in summer the focus of local thunder showers.
Metaphysics, again, is concerned with the ultimate problems of matter and spirit; it endeavours to go behind the phenomena of sense and focus its attention on the fundamental truths which are the only logical bases of natural science.
The focus of Polish nationality was now transferred from Warsaw, where the Targowicians and their Russian patrons reigned supreme, to Leipzig, whither the Polish patriots, Kosciuszko, Kollontaj and Ignaty Potocki among the number, assembled from all quarters.
The Trades Hall at Carlton is the meeting-place of the trades-union societies of Victoria, and is the focus of much political influence.
It is the inverse of a central conic for the focus, and the first positive pedal of a circle for any point.
He first brought the revolutions of our satellite within the domain of Kepler's laws, pointing out that her apparent irregularities could be completely accounted for by supposing her to move in an ellipse with a variable eccentricity and directly rotatory major axis, of which the earth occupied one focus.
If on emergence the different portions he brought together at the focus it is obvious that the optical action must be in every respect similar to that of a grating when the nth order of spectrum is considered.
In order to record line spectra it is by no means necessary that the receiving instrument (bolometer or radiometer) should be linear in shape, for the separation of adjacent lines may be obtained if the linear receiver be replaced by a narrow slit in a screen placed at the focus of the condensing lens.
In one solution of the former problem is the first recorded use of the property of a conic (a hyperbola) with reference to the focus and directrix.
A different arrangement, used in the instrument described below, consists in having the magnet hollow, with a small scale engraved on glass firmly attached at one end, while to the other end is attached a lens, so chosen that the scale is at its principal focus.
The position of the magnet is observed by means of a small telescope, and since the scale is at the principal focus of the lens, the scale will be in focus when the telescope is adjusted to observe a distant object.
Thus no alteration in the focus of the telescope is necessary whether we are observing the magnet, a distant fixed mark, or the sun.
to Florence was of extreme importance; for this town was the real home of the new art, and the intellectual focus of all the humanistic movements in Italy.
The two achromatic lenses, C and D, bring the rays to a focus on the plane surface of the large lens, E, forming an image there.
In shape Milan is a fairly regular polygon, and its focus is the splendid Piazza del Duomo, from which a number of broad modern streets radiate in all directions.
The Kongens Nytorv, the focus of the life of the city and the centre of road communications, is an irregular open space at the head of a narrow arm of the harbour (Nyhavn) inland from the steamer quays, with an equestrian statue of Christian V.
Thus Kandahar becomes a sort of focus of all the direct routes converging from the wide-stretching western frontier of India towards Herat and Persia, and the fortress of Kandahar gives protection on the one hand to trade between Hindustan and Herat, and on the other it lends to Kabul security from invasion by way of Herat.
The forum at Pompeii was, as at Rome itself and in all other Italian cities, the focus and centre of all the life and movement of the city.
The Piazza Ferrari, a large irregular space, is the chief focus of traffic and the centre of the Genoese tramway system; it is embellished with a fine equestrian statue of Garibaldi, unveiled in 1893, which stands in front of the Teatro Carlo Felice.
It superseded Babylon as the industrial focus of Babylonia and counted some 600,000 inhabitants (plebs urbana) according to Pliny, N.H.
The king was the emblem, the focus and the bond of national unity; and to preserve it men were ready to put up with vagaries which to other ages seem intolerable.
1, where P is a point on the curve equidistant from the fixed line AB, known as the directrix, and the fixed point F known as the focus.
The line CD passing through the focus and perpendicular to the directrix is the axis or principal diameter, and meets the curve in the vertex G.
The line FL perpendicular to the axis, G D and passing through the focus, is the semilatus rectum, the latus rectum being the focal chord parallel to the directrix.
It also follows that a line half-way between a point and its polar and parallel to the latter touches the parabola, and therefore the lines joining the middle points of the sides of a self-conjugate triangle form a circumscribing triangle, and also that the ninepoint circle of a self-conjugate triangle passes through the focus.
The pedal equation with the focus as origin is p 2 =ar; the first positive pedal for the vertex is the cissoid and for the focus the directrix.
William Gascoigne was the first who practically appreciated the chief advantages of the form of telescope suggested by Kepler, viz., the visibility of the image of a distant object simultaneously with that of a small material object placed in the common focus of the two lenses.
focus, but it does not appear that they were ever able to use them in practical observations.
focus, and in 1789 his great reflector of 4 -ft.
When the axis of the eye-lens coincides with that of the object-glass, and the focal point of the eye-lens is coincident with the principal focus of the object-lens, parallel rays.
telescope has been adjusted to focus upon a star, and to divide the diameter of the object-, glass by the diameter of the emergent pencil.
For normal eyes the natural adaptation is not to focus for quiteparallel rays, but on objects at a moderate distance, and practically, therefore, most persons do adjust the focus of a telescope, for most distinct and easy vision, so that the rays emerge from the eye-piece very slightly divergent.
This want of proportion in the dispersion for different regions of the spectrum is called the "irrationality of dispersion"; and it is as a direct consequence of this irrationality, that there exists a secondary spectrum or residual colour dispersion, showing itself at the focus of all such telescopes, and roughly in proportion to their size.
When all is taken into consideration it is scarcely possible to reduce the secondary colour aberration at the focus of such a double object-glass to less than a fourth part of that prevailing at the focus of a double objective of the same aperture and focus, but made of the ordinary crown and flint glasses.
focal length a discrepancy of I unit in the 3rd decimal place in the above proportional figures would cause a linear error in the focus for that colour of only about .025 in., so that the largest deviation implied by the tables would be a focus for the extreme violet H ray about 037 longer than the normal.
The focus of A for parallel rays is at F, that of B for parallel rays at f - between B and F.
showed that, if the large mirror were a segment of a paraboloid of revolution whose focus is F, and the small mirror an ellipsoid of revolution whose foci are F and P respectively, the resulting image will be plane and undistorted.
collimator of long focus.
Parallel rays falling on A A converge on the plane mirror B B, and are thence reflected at Ne w right angles to the axis, forming an image in the focus of i the eye-piece E.
A A is a concave parabolic mirror, whose axis a c is inclined to the axis of the tube a b so that the image of an object in the focus of the mirror may be viewed by an eye-piece at E, the angle b a c being tier equal to the angle c a E.
focus, and on a much smaller scale by Warner & Swasey for the Bruce telescope of io-in.
focus, made for the Yerkes Observatory.
focus, but for certain classes of work it is desirable to have the advantage of greater focal length.
2, and come to focus on the slit of the powerful spectroscope that is mounted on a pier in the chamber of constant temperature as shown in fig.
21 (d); in this case a convex mirror of different curvature is employed, the equivalent focus of the combination being 80 ft.
Within the focus of the object-glass is a right-angled prism of total reflection, which diverts the converging rays from the object-glass at right angles to the axis of the telescope, and permits the observing micrometer n to be mounted in the very convenient position shown in the figure.
In 17 9 3 the city was the focus of the Girondist movement against the Convention.
As a consequence the city became the chief focus of enterprise and foreign progress.
If the source be a point, such as the image formed by a lens of small focus or by a fine hole in a plate held close to a bright flame, the outline of the shadow is to be found by drawing straight lines from the luminous point so as to envelop the opaque body.
The most densely peopled region and the focus of civilization is the lacustrine depression and the surrounding uplands.
In fact dissemination seems to have taken place, as usual, by the conversion of one house after another into a focus of disease, a process favoured by the fatal custom of shutting up infected houses with all their inmates, which was not only almost equivalent to a sentence of death on all therein, but caused a dangerous concentration of the poison.
The focus of the movement was the Maros region, where the rebel Ajtony built the fortress of Marosvar.
Now in a conic whose focus is at 0 we have where 1 is half the latus-rectum, a is half the major axis, and the upper or lower sign is to be taken according as the conic is an ellipse or hyperbola.
This is recognized as the polar equation of a conic referred to the focus, the half latus-rectum being hf/u.
Thus for a circular orbit with the centre of force at an excentric point, the hodograph is a conic with the pole as focus.
To illustrate this subject, it may be mentioned that an ellipse rotating about one focus rolls completely round in outside gearing with an equal and similar ellipse also rotating about one focus, the distance between the axes of rotation being equal to the major axis of the ellipses, and the velocity ratio varying from to I ~eccentricitY an hyperbola rotating about its further focus rolls in inside gearing, through a limited arc, with an equal and similar hyperbola rotating about its nearer focus, the distance between the axes of rotation being equal to the axis of the hypereccentricity + I
unity; and a parabola rotating about its focus rolls with an equal and similar parabola, shifting parallel to its directrix.
He investigated the optical constants of the eye, measured by his invention, the ophthalmometer, the radii of curvature of the crystalline lens for near and far vision, explained the mechanism of accommodation by which the eye can focus within certain limits, discussed the phenomena of colour vision, and gave a luminous account of the movements of the eyeballs so as to secure single vision with two eyes.
The area of this seismic disturbance extended over north-eastern India, from Manipur to Sikkim; but the focus was in the Khasi and Garo hills.
On this account the lines D and G' are united for ordinary photographic objectives; the optical as well as the actinic image is chromatically inferior, but both lie in the same place; and consequently the best correction lies in F (this is known as the " actinic correction " or " freedom from chemical focus ").
If we write r for PN, then y= r cos a, and equation 9 becomes 13.7,T - I) This relation between y and r is identical with the relation between the perpendicular from the focus of a conic section on the tangent at a given point and the focal distance of that point, provided the transverse and conjugate axes of the conic are 2a and 2b respectively, where a= p, and b 2 = -.
Hence the meridian section of the film may be traced by the focus of such a conic, if the conic is made to roll on the axis.
i I); the internal pressure is equal to the external pressure, and the tension along the axis is equal to 27rTm where m is the distance of the vertex from the focus.
towards the focus of production, the chemiotaxis is termed positive; when the converse obtains, negative.
tive than the first, is an ellipse having the luminous point for a focus, and its centre at the foot of the perpendicular from the luminous point to the refracting line.
If the second medium be more highly refractive than the first, the secondary caustic is a hyperbola having the same focus and centre as before, and the caustic is the evolute of this curve.
It became the bulwark of the The revolt Protestant faith in the Netherlands, the focus of the of the resistance to Spanish tyranny.
This inferiority of the Gregorian he explained as being probably due to the mutual interference of the rays as they crossed at the principal focus before reflection at the second mirror.
From this time the country was never tranquil, and Ahmednagar became the focus of constant rebellions.
He then points out why " the object-glass of any Telescope cannot collect all the rays which come from one point of an object, so as to make them convene at its focus in less room than in a circular space, whose diameter is the 50th part of the Diameter of its: Aperture: which is an irregularity some hundreds of times greater, than a circularly figured Lens, of so small a section as the Object-glasses of long Telescopes are, would cause by the unfitness of its figure, were Light uniform."
a conic section (or as we now say a " conic ") is the locus of a point such that its distance from a given point, the focus, is in a given ratio to its (perpendicular) distance from a given line, the directrix; or it is the locus of a point which moves so as always to satisfy the foregoing condition.
The points called foci presented themselves in the theory of the conic, and were well known to the Greek geometers, but the general notion of a focus was first established by Plucker (in the memoir " Uber solche Puncte die bei Curven einer hdheren Ordnung den Brennpuncten der Kegelschnitte entsprechen " (Crelle, t.
We may from each of the circular points draw tangents to a given curve; the intersection of two such tangents (belonging of course to the two circular points respectively) is a focus.
Thus the general curve of three bar-motion (or locus of the vertex of a triangle, the other two vertices whereof move on fixed circles) is a tricircular sextic, having besides three nodes (m = 6, 6 = 3+3+3, = 9), and having the centres of the fixed circles each for a singular focus; there is a third singular focus, and we have thus the remarkable theorem (due to S.
His method was to sift out the long dark waves which are associated with the short visible waves constituting the light of the sun or of the electric arc and to concentrate the former to a focus.
If the eye was placed at the focus, no sensation of light was observed, although small pieces of charcoal or blackened platinum foil were immediately raised to incandescence, thus giving rise to visible rays.
The arc being struck in the usual way between two carbons, a concave mirror, placed close behind it, caused a large part of the radiation to be directed through an aperture in the camera and concentrated to a focus outside.
Any small body which was a good absorber of dark rays was rapidly heated to redness when placed at the focus.
Since the rays used by Tyndall in these experiments are similar to those emitted by a heated body which is not hot enough to be luminous, it might be thought that the radiation, say from a hot kettle, could be concentrated to a focus and employed to render a small body luminous.
For it is easy to see that if, by means of lenses of rock-salt or mirrors, we focused all or nearly all the rays from a small surface on to another surface of equal area, this would not raise the temperature of the second surface above that of the first; and we could not obtain a greater concentration of rays from a large heated surface, since we could not have all parts of the surface simultaneously in focus.
The doctrine of Atonement, destined to be the focus of Protestant evangelicalism, has remained undefined in Catholic circles,' an implicate or presupposition, but no part of the explicit and authorized creeds.
The Jacobin Club was reopened and became once more the focus of disorder.
A body can move round the sun in an elliptic orbit having the sun in its focus, and describing equal areas in equal times, only under the influence of a force directed towards the sun, and varying inversely as the square of the distance from it.
If projected with this velocity in any direction the point of projection will be at the end of the minor axis of the orbit, because this is the only point of an ellipse of which the distance from the focus is equal to the semi-major axis of the curve, and therefore the only point at which the distance of the body from the sun is equal to its mean distance.
These rays come to a focus at a point F lying in the focal plane of the telescope.
He long adhered to the traditional belief that all celestial revolutions must be performed equably in circles; but a laborious computation of seven recorded oppositions of Mars at last persuaded him that the planet travelled in an ellipse, one focus of which was occupied by the sun.
And, since the focus of his almost universal thought and inquiry and of his rich culture and varied life was religion and theology, he must be regarded as the classical representative of modern effort to reconcile science and philosophy with religion and theology, and the modern world with the Christian church.
In Dalmatia, where the Ragusan journal Slovinac has served, like the Agram Rad, as a focus of literary activity, there have been numerous poets and prose writers, associated, in many cases, with the Illyrist or the nationalist propaganda.
Thus for nearly six centuries it was Mistra and not Sparta which formed the centre and focus of Laconian history.
eccentricity less than unity: this involves the notion of one directrix and one focus; (2) the ellipse is the locus of a point the sum of whose distances from two fixed points is constant: this involves the notion of two foci.
To investigate the form of the curve use may be made of the definition: the ellipse is the locus of a point which moves so that the ratio of its distance from a fixed point (the focus) to its distance from a straight line (the directrix) is constant and is less than unity.
I) be the directrix, S the focus, and X the foot of the perpendicular from S to KX.
line K'X' parallel to KX such that AX = A'X', then the same curve will be described if we regard K'X' and S' as the given directrix and focus, the eccentricity remaining the same.
the square on the semi-major axis equals the rectangle contained by the distances of the focus and directrix from the centre; and 2a = SP+S'P, where P is any point on the curve, i.e.
Of the properties of a tangent it may be noticed that the tangent at any point is equally inclined to the focal distances of that point; that the feet of the perpendiculars from the foci on any tangent always lie on the auxiliary circle, and the product of these perpendiculars is constant, and equal to the product of the distances of a focus from the two vertices.
A focus or directrix is equal to two conditions; hence such problems as: given a focus and three points; a focus, two points and one tangent; and a focus, one point and two tangents are soluble (very conveniently by employing the principle of reciprocation).
Of practical importance are the following constructions: - (I) Given the axes; (2) given the major axis and the foci; (3) given the focus, eccentricity and directrix; (4) to construct an ellipse (approximately) by means of circular arcs.
2) be the focus, KX the directrix, X being the foot of the perpendicular from S to the directrix.
One definition, which is of especial value in the geometrical treatment of the conic sections (ellipse, parabola and hyperbola) in piano, is that a conic is the locus of a point whose distances from a fixed point (termed the focus) and a fixed line (the directrix) are in constant ratio.
In the case of the circle, the centre is the focus, and the line at infinity the directrix; we therefore see that a circle is a conic of zero eccentricity.
If one of the foci be at infinity, the conics are confocal parabolas, which may also be regarded as parabolas having a common focus and axis.
His proofs are generally long and clumsy; this is accounted for in some measure by the absence of symbols and technical terms. Apollonius was ignorant of the directrix of a conic, and although he incidentally discovered the focus of an ellipse and hyperbola, he does not mention the focus of a parabola.
The focus of the parabola was discovered by Pappus, who also introduced the notion of the directrix.
Descartes (Dioptrique, 1637) describes microscopes wherein a concave mirror, with its concavity towards the object, is used, in conjunction with a lens, for illuminating the object, which is mounted on a point fixing it at the focus of the mirror.
Antony van Leeuwenhoek appears to be the first to succeed in grinding and polishing lenses of such short focus and perfect figure as to render the simple microscope a better instrument for most purposes than any compound microscope then constructed.
focus, is here N = tan w'/tan w = y/f.4/y=4/f=4 Thus, while a lens of i in.
For lenses of short focus the diameter of the pupil is too large, and diaphragms must be employed which strongly diminish the aperture of the pencils, and so reduce the errors, but with a falling off of illumination.
In this manner lenses of short focus can be produced having lower curvatures than glass lenses necessitate.
The spherical aberration of a diamond lens can be brought down to one-ninth of a glass lens of equal focus.
Where very short focus simple microscopes are employed, using high magnifications, it is imperative to employ a stand which permits exact focusing and the use of a special illuminating apparatus.
A microscope objective being made in essentially the same way as a simple microscope, and the front focus of the compound system being situated before the front focus of the objective, the magnification due to the simple system makes the free object distance greater than that obtained with a simple microscope of equal magnification.
13, the objective L1 forms a real magnified image O'Oi'; the object OO l must therefore lie somewhat in front of the front focus F1 of the objective.
In this case the optical tube length equals the distance of the adjacent focal planes of the two systems, which equals the distance of the image-side focus of the objective F 1 ' from the object-side focus of the eyepiece F2.
F2 = front focus of eyepiece.
But as the object-side focus F2 lies behind the eyepiece, the real image is not produced, but the converging pencils from the objective are changed by the eyepiece into parallels; and the point 0 1 in the top of the object y appears at the top to the eye, i.e.
With powerful systems, object-points lying quite near the plane focused for would be represented by such large dispersion circles that practically only the points lying in one plane appear simultaneously sharp; and it is only by varying the focus that the object-points lying in other planes can be observed.
To ensure the telecentric transmission, the diaphragm in the back focus of the objective may be replaced by a diaphragm in the front focal plane of the condenser, supposing that uniformly illuminated objects are being dealt with; for in this case all the principal rays in the object-space are transmitted parallel to the axis.
As the exit pupil ['P i ' for the objective lies before the front focus of the eyepiece, generally at some distance and near the objective, the eyepiece projects a real image from it behind its image-side focus, so that if this point is accessible it is the exit pupil P"P i ".
in the object-space the objective has telecentric transmission, the exit pupil must coincide with the back focal plane of the combined system, and it always lies behind the image-side focus of the eyepiece.
Points of a small object (compared with the focus of the objective) send to the objective wide pencils.
The rays emitted from an axial object-point are not combined into one image-point by an ordinary biconvex lens of fixed aperture, but the central rays come to a more distant focus than the outer rays.
For this reason Amici constructed objectives of a similar aperture and focus for different thicknesses of glass covers.
The alteration of the focus and the aperture are little influenced.
These eyepieces are very convenient in use, for when they are changed the lower focus always falls in about the same plane.
that the source falls approximately at the front focus of this lens and consequently is represented at infinity through the illuminating lens.
For slight magnifications rough adjustment is sufficient, but with objectives of a focus below 4 in., a fine adjustment is wanted.
The image produced by the microscope objective M in its back focus plane is then observed through a supplementary microscope.
The distance of the object from the nearer focus of the objective is next determined.
This distance is composed of the distance of the object from the centre of the plane mirror, and of the distance of the focus of the objective on the stage plate from the centre of the plane mirror.
Let the size of the object be y, the size of the image y' the distance of the object from the focus x, then y/y'=x/f i from which f l can be calculated (see Lens).
north-east of it, are the massive ruins of Norham Castle, made famous by Scott's Marmion, and from the time of its building by Ranulph Flambard in 1121 a focus of Border history during four centuries.
However extraordinary it may appear, especially to those who bring the living forms only into focus, that opposition should still be made to Huxley's primary division of the vertebrates other than mammals into Sauropsida (birds and reptiles) and Ichthyopsida (batrachians and fishes), it is certain that recent discoveries in palaeontology have reduced the gap between batrachians and reptiles to such a minimum as to cause the greatest embarrassment in the attempt to draw a satisfactory line of separation between the two; on the other hand the hiatus between fishes and batrachians remains as wide as it was at the time Huxley's article Amphibia (Encyclopaedia Britannica, 9th ed.) was written.
Magdeburg, therefore, became the focus of the whole campaign of 1631; but the obstructive timidity of the electors of Brandenburg and Saxony threw insuperable obstacles in his way, and, on the very day when John George I.
After a moment his focus came back to her face.
With everyone in good health again, the focus shifted back to preparing for the new babies.
Howie is our prime focus but I'll direct his activities.
Damian forced himself to focus on Dusty, though he wanted nothing more than to wrap his hands around the newbie's neck.
Darkyn was listening with the focus of a predator, his sharpened teeth resting on his lower lip.
The tears stopped of their own accord after a while, and the calm of her mind brought back her focus.
In his blood-filled haze, he heard one of his brothers shout, and the demons shift their focus from Kris.s small groupâ€”which Rhyn defendedâ€”to the warriors pouring out of portals onto the small battlefield.
She sensed Evelyn's sudden melancholy and tried to focus.
"But I'm not done â€“" Rhyn snatched the open can of food and flung it into the forest. Toby stared at him then took his pink coat and crawled deeper into the little cave. Rhyn stretched out on his back next to the fire, his mind puzzling over the angel's words. However much he tried to focus on what it was Death had agreed to, he couldn't escape his mixed emotions or one errant thought.
The idea of caring for her overwhelmed him again. He'd never had a reason to try to control his power or to focus on anything other than surviving. That a simple little mortal could show him just how little his Immortal and demon powers really meant humbled him. If he found his way, it would be because of her. Her distress and sorrow were, buried but he still saw them. She was trying to be brave, asking him for one last moment of comfort before what she thought was the end.
Dean found it difficult concentrating on the expense reports with Fred's foot keeping time against the coffee table to an early cut of Hank Williams, but gradually his mind began to focus on the forms.
Like Carmen, their concept of friendship was two-way, with more focus on giving than receiving.
It was best to focus on the things within her grasp â€“ like Alex.
Now that he had a place and knew what the Watchers wanted, he could focus on his next item of business: finding and killing a few Others.
They're going to stop attacking Guardians, too, and they're going to focus on Darian.
She'd given up her own, and to invite hope when she needed to focus on stopping the demon for goodâ€¦her resolve was too brittle to consider any other fate.
Unable to focus on anything, Jessi found herself almost too drained to remember the name of the Guardian who approached her.
It meshed well with Russia's traditional primary focus on relations with the United States and was reinforced by apparent ideological affinity.
A similar ascertainment bias appears to be present in the exclusive focus on HIV.
What if its efforts to become more diverse and inclusive alienate existing members without providing a sufficiently coherent focus to attract a new membership?
A focus group corroborated the survey results by saying they thought the ad was "very easy to understand."
This helps to improve diction, organize what they want to say and focus on the main points of interest.
Auril's main focus is to lobby government and industry leaders on university/industry research.
Business Inc. uses advanced tools to help the demands of the artist, which enable him/her to focus on the creation.
It will influence decisions on whether to begin new groups or focus on capacity building of existing groups.
To appreciate the color and structure, focus on its many nuances.
No item is too humble nor too prodigious for Philippe Starck to focus his extraordinary talents on.
Feel a warmth in your upper abdomen; breathe; focus.
Such discrimination, whether we focus on it or not, is morally abhorrent.
This approach makes use of most people's ability to determine sharp focus for themselves, minimizing the need for highly trained and scarce personnel.
abilityvent was a great success providing a unique opportunity for our senior managers to focus on enhancing their leadership abilities.
Life has been smart to focus on the issue of abortion for fetal abnormality.
It also supplied a focus for those painters who, whatever their merits, had not been thought fit to invite to become academicians.
activityesearch areas The research activities focus on issues concerning aging.
Viewfinder diopter adjustment Adjust the focus of the viewfinder by ±1.
Once the dioptre adjustment has been set, the main central wheel will focus both eyes equally.
The interior of the kirk was clearly designed to have little adornment to distract worshippers from their focus on the minister.
The word I focus on in the example is away, which has been traditionally called a directional adverb.
It was urged that studies should focus on the fine and ultrafine fractions of the ambient aerosol and on effects on sensitive individuals.
Pilates will not only benefit muscle tone and strength but will also focus on breathing and postural alignment.
In my animal pieces I focus on the physical articulation of creatures, whilst my figures are also allegorical.
Determination and a strong focus are therefore all-important attributes.
This reflects the eminently political nature of EU budgetary allocations at the expense of a true poverty focus.
ambiences: It will focus on the value of the main benefits, physical fitness and journey ambiance.
ampersand event will focus on internet marketing for creative businesses.
Anyone wishing to focus on systematic observations of reptiles and/or amphibians would be very welcome.
Mixed metal oxides and phases containing mixed anions, such as oxide fluorides, provide our current focus.
A major focus of his work is on the formation of the dorsal aorta and the generation of adult blood stem cells during embryogenesis.
apology>Apologies for the absence of a " Diary " in the last Focus.
Most clinical trials focus on the role of homeopathic arnica but more recently the use of topical herbal products has been examined.
asana sequence with focus on gaining a deeper understanding of how the chakras and energy relate to different postures.
The focus of this report is the interim qualitative evaluation of the facts aspirin program, promoting the use of aspirin in secondary prevention.
rest assured IN THE KNOWLEDGE THAT ALL 1&1 SYSTEMS ARE OPTIMIZED ALLOWING YOU TO FOCUS YOUR ATTENTION ON BUSINESS MATTERS.
The focus group research showed that people did not know that many eye diseases are often asymptomatic.
Abraham did not want to focus attention on the ram.
Ot uses the term avant-garde to indicate its focus on artists and art movements that have led the filed in breaking with successive traditions.
Most adults with food aversion focus on meat or greasy foods.
The focus of these meeting revolved around issues related to merging special education content and activities into the post baccalaureate methods courses.
The pop singer added that he wanted to see an extensive program with a focus on local unsigned bands " .
The second of our unsigned events focus's on the non-stop barrage of rock bands coming out of Britain in 2004.
The focus of the coming months is laying the policy basis for the legislation.
One thing that always befuddles me is the lack of focus many site pages have... .
A focus solely on congestion reduction may bring economic benefits to some road users; it will not necessary improve the safety of all.
bifocal spectacles you end up like a nodding donkey trying to focus on different parts of a screen!
One main focus of our research is on enzymes involved in tetrapyrrole biosynthesis.
While we do not exclude active trail blazers, we initially focus more on paths built up as a passive by-product of everyday activity.
Its focus was to draw up a detailed blueprint for devolution.
An optical telescope is used with a special detector called a bolometer placed at its focus.
These focus the attention on the shoulders and cleavage area, which can be enhanced by wearing a push-up bra.
A film crew, making a documentary for Japanese TV on canal restoration in the UK, focus on the trainee bricklayers.
Bite-sized brouhaha as was responsible to electric kool-aid acid focus on alcoholics ' .
Orange Power: Sea buckthorn berries Beautifully orange-coloured sea buckthorn berries have been in the focus of European research.
News: Trimble demands arms action now Why do the bombing buffoons focus so often on Ealing?
In the focus groups, train fares were a particular bugbear: Train prices are unbelievable Tubes are better than trains.