V. Fill in the blanks:

1. Historically, distances were measured using … , for instance measuring tapes made of steel or invar.

2. … , the surveyor might have to "break" (break chain) the measurement - that is, raise the rear part of the tape upward, plumb from where the last measurement ended.

3. Historically, horizontal angles were measured using … , which would provide a …, from which deflections could be measured.

4. A compass was later …, through scribed discs providing …, mounting telescopes with reticles, levels and calibrated circles allowing measurement of vertical angles.

5. The simplest method for measuring … is with an altimeter.

6. Levels are calibrated to provide a … from which differentials in height between the instrument and the point in question can be measured.

7. With a …, set on a tripod, one can measure angles (horizontal and vertical).

8. A more modern instrument is a …, which is a theodolite with an electronic distance measurement device (EDM) and can also be used for … when set to the horizontal plane.

9. Modern top-of-the-line total stations are fully … .

10. … do not work in areas with dense tree cover.

11. A faster way to measure (no obstacles) is with a helicopter with … .

VI. Write down the annotation to the text. Use the following phrases:

The headline of the text I have read is …

The text is about …

According to the text …

The purpose of the text is to give some information about …

I think …

From my point of view …

This information is new (not new) for me.

I think I could use this information (in my practical work, in my studies, in my professional training).

I found the text useful (interesting, important, dull, too hard to understanding).

Unit xiiI

Compass

I. Learn the following words and word combinations:

pointer – стрілка

face – циферблат

cardinal points – сторони світу

conjunction – поєднання

longitude – довгота

sextant – секстант

latitude – широта

stand-alone sealed instrument – автономний герметичний прилад

bar - стержень

needle – стрілка

pivot – обертатися на осі

enhancement – покращення

compass dial - диск компаса

sundial – сонячний годинник

ruggedized – міцний

transparent – прозорий

baseplate – плита

field setting – польові умови

to detect – визначати

optional – додатковий

true north – географічна північ

stray – перешкода

circuit – схема, ланцюг

true north – географічна північ

II. Find English equivalents of these words combinations in the text:

Магнітне поле, навігаційний інструмент, сторони світу, морський хронометр, навігаційні можливості, морська торгівля, рідинний компас, чутливий пристрій, магнітна північ, ізольований інструмент, особливий інструмент, прозора пластина, польові умови, рухливі частини, ресивери глобальної системи навігації та визначення місцезнаходження, додаткова підсистема

Compass

A compass, (or mariner's compass) is a navigational instrument for finding directions on the Earth. It consists of a magnetized pointer free to align itself accurately with Earth's magnetic field, which is of great assistance in navigation. The face of the compass generally highlights

the cardinal points of north, south, east and west. A compass can be used in conjunction with a marine chronometer to calculate longitude and a sextant to calculate latitude, providing a very accurate navigation capability. This device greatly improved maritime trade by making travel safer and more efficient. An early form of the compass was invented in China in the 11th century. The familiar mariner's compass was invented in Europe around 1300, from whence later originated the liquid magnetic compass. Fundamentally, the classic compass is any magnetically sensitive device able to indicate the direction of the magnetic north of a planet's magnetosphere. Often compasses are built as a stand-alone sealed instrument with a magnetized bar or needle turning freely upon a pivot, or floating in a fluid, thus able to point in a northerly and southerly direction. Many enhancements have been developed. A compass dial is a small pocket compass with a sundial. A variation compass is a specific instrument of a delicate type of construction. It is used by observing variations of the needle. An Orienteering compass consists of a ruggedized needle compass permanently attached to a transparent baseplate containing tools to assist the user in working with maps in a field setting (as opposed to in an office at a desk).

A recent development is the electronic compass, which detects the magnetic directions without requiring moving parts. This device frequently appears as an optional subsystem built into Global Positioning Satellite Receivers (GPSRs). There are other, more accurate, devices for determining north (known in such cases as true north, as opposed to magnetic north), which do not depend on the earth's magnetic field for operation. A gyrocompass (ships) or astrocompass (aircraft) can be used to find true north, while being unaffected by stray magnetic fields, nearby electrical power circuits or nearby large masses of ferrous metals.