Like all sounds, speech also consists of sound waves. The mouthpiece of the telephone has a microphone, which converts the spoken sounds into electrical current. The transmission of electric current is done through wires. In the earpiece, the electric current is converted back to sound waves. Earlier, the wires were made of copper, but today telephonic conversations are transmitted through glass fibre cables or even via satellite connections. Telephone calls over long distances were earlier possible only through telephone operators. Since 1970, however, we can make overseas calls directly. The telephone was invented by Graham Bell, who applied for its patent in 1876.
Don’t you think a book is much more interesting if it has lots of pictures? Pictures or 
illustrations also make it easier to understand things. The manuscripts of ancient times which were decorated with elaborate initials, miniature illustrations and borders were called illuminated manuscripts. Sometimes, these decorations were even made with gold and silver!Very early printed books were sometimes produced with spaces left for miniatures, or were given illuminated initials or decorations in the margin. Illustrated printed books began to appear in the late 15th century, in Germany and Italy. In earlier times, some books had been published from woodcuts, with text and illustration all carved on a single block. Early type-printed books were illuminated by hand. However, this was very expensive. Although many early printed books, like the Gutenberg Bible, relied on hand-coloured illustrations, others quickly integrated the new printing, using moveable type for the letters, with the older woodcut traditions. Another early technique was etching, in which the lines of the picture were cut into a copper plate with acid. In either case, ink was spread over the carved illustration and applied to the paper
Typesetting is a presentation of text on paper or some other material, in a printed form. The word 
‘type’ is used to denote a small block of metal or wood, bearing a raised letter or number on the upper end that leaves a printed impression when inked and pressed on paper. We know that by the middle of the 15th century, movable type had been invented in Europe by the German printer, Johann Gutenberg. By 1462, Gutenberg’s invention became accepted and the use of it spread throughout Europe. Movable type is also called foundry type or hot type. In foundry type, each piece of type was cast into a precise size from metal which was an alloy of lead, tin, and antimony. Each piece contained a raised image of a single letter, number, or other character. In setting type, letters were selected one at a time, and lined up in what was called a composing stick until it was almost full. Then, by using pieces of type with no face on them, spaces between words were adjusted to bring the line to the required length. Each line of type was placed by hand in a larger box made especially for housing the type. The individually lines were laid out exactly like the page should look except that the type was backwards as if looking at it in a mirror. The type was then inked and copies made directly from the type. When printing was finished, the type was taken apart, cleaned, and returned to the distribution box to be used again another time
The ancient Phoenicians had an arrow-like symbol in their alphabet. It was the seventh letter, and called ‘zayin’. The ancient Greeks adopted this symbol from the Phoenicians as the sixth letter of their alphabet in 8000 BC. They called it ‘zeta’, and gave it its present form. The Romans adopted it from the Greek alphabet in 100 AD, and Z is the last letter of the Roman alphabet to this day. ‘Z’ is pronounced as ‘zed’ by the British and as ‘zee’ in America. If you are sending a Morse code, you will have to send two dashes and two dots to present ‘Z’! Another interesting fact about ‘Z’ is that it was used to represent the Roman number 2000 in medieval times.
The earlier flags of the Indian navy had the St. George’s Cross on them, and these were changed 
to an anchor within a frame surmounted by the state emblem, the Sarnath Lion.The navy blue Indian Naval Crest is also found in the flags of flag officers. Admirals fly a white flag with the red horizontal and vertical bars and the chakra in the middle. The flag of the vice admiral is similar to the Admiral’s flag with a red ball added. Rear Admirals, Commodores and senior officials all have their own flags too. The Navy also its different badges for different positions, gunner, radar plotter, torpedo and anti-submarine officers, survey records, etc.
Many political and social movements use flags to get noticed, to attract more people, and to unify its
members. The socialist movements use red flags to represent their cause. Anarchists use black flags to get attention.
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