Find the non-finite forms of the verb in the text and define their functions.

5. Translate the following words and define what parts of speech they are:

electrify, electricity, electrical, electrically; scientist, scientific, scientifically, science; vary, various, variable, va­riety; invent, inventor, inventiveness; appliance, application, apply, applicable

6. Write out the adjectives with the suffix -able from the text. Translate them.

7. Fill in the blanks with either should or would and translate the following sentences:

1. It ... be hard to say when windmills were first used as a source of mechanical power. 2. In order to generate electric current the power of some kind ... be utilized. 3. The solution of the problem ... require further studies on the part of scientists and engineers. 4. One ... mention here the three principal effects which an electric current produces. 5. If some current flowed along a thin wire and then that same amount of cur­rent were sent through a thicker one, a different quantity of heat... be developed. 6. It ... be quite wrong to think that electric power is the only possible source of heat. 7. One ... be careful when operating this engine. 8. I... like to turn your attention to the use of new sources of power.

8. Answer the following questions:

1. What are the main sources of electric power? 2. Why are the engineers looking for new sources of power? 3. What fuels do you know? 4. What are the new sources of power? 5. For what purpose can the power of wind be used? 6. What is the principal disadvantage of wind power? 7. When did the wind­mills first come into use? 8. Have you ever seen a windmill In operation?

9. Work in pairs. Put questions to your fellow-student and let him answer them:

1. what sources of power he knows.

2. if the chemical sources of power have a limited appli­cation.

3. if velocity influences the efficiency of a wind-power plant.

4. if natural gas and wood are the new sources of power.

5. what amount of wind power finds an efficient appli­cation under present conditions.

6. if the windmills were first utilized as a source of electri-¹ cal power?

7. where a large turbine powered by the wind was built in our country.

8. what factors reduce the efficiency of a wind-driven power plant.

9. if a windmill can be used for power generation.

10. Translate the following word combinations and use them in the sentences of your own:

gas turbine, iron bar, liquid state, power distribution, heat power, wind speed, power generation, heat power plant

11. Describe the construction and the operation of a wind-power plant.

LESSON TWENTY-FOUR

TIDAL POWER PLANTS

The main purpose of this article is to give some idea of one more natural source of electric power and the existing methods, ways and means of its use.

Coal, oil, wind, water and atomic power — these are fa­miliar sources of power, but what is tidal power?

The periodic rise and fall of the ocean on a coast line is well known. In the open ocean the changes in level amount to only about 61 cm, or so. On the coasts of continents it is often much greater. At any rate, tides like wind will last for ever.

Utilization of tidal power has been studied more or less extensively in a number of countries, such as the Russian Federation, the USA, France, Canada, England, and others. The fact is that tidal forces are expected to make considerable contribution if not to present-day, at least to future electricity production. By intercepting ocean or sea water at high tide in a basin and directing it back through turbines at low tide, one could create a kind of a working hydro-electric plant.

Although there are tides along all coasts of all continents, not all places possess the necessary qualities for the installation of an efficient, reliable and economical tidal power plant. The most important features are the amplitude of the tide, the surface area of the basin, and the size of the dam required. The higher the tide, the larger the area of the available basin, and the smaller the dam required, the better the locality. Suitable places can be found, for instance, on the French coast and it is probably there that a big t. e. s. was con­structed.

Russian tidal power sources are among the great­est in the world. No wonder that several large tidal power plants are planned here. Kislaya Bay on the Barents Sea was found to be the very place for the construction of the first experimental t. p. s. At high tide water from the Barents Sea will flow in through an operating turbine, while at low tide the water will be conducted back to the sea through that very turbine, making it work in both directions. Such a turbine makes it possible to use both high and low tides to the best advantage.

The Kislaya Bay station is an experimental project and Its planned capacity is not large. But that is not the principal thing. What is important is the possibility of testing the design of the station under consideration. The results obtained will enable designers to solve the main problems for several other powerful and super powerful tidal plants to go into oper­ation in future. One cannot help mentioning in this connection the Belomorsky project of a t. e. s. which is to have a power capacity greater than that of Bratsk, the biggest hydro-electric station in the world.

Exercises

1. Learn the following active words:

Area (n) район, участок

Coast line береговая линия

Dam (n) плотина

Design (n, v) проект

Enable (v) давать возможность

Level (n) уровень

local­ity (n) местность, район

rise (n) подъем, повышение

tide (n) прилив и отлив

utilization использование