“Everything we are today, we owe to the inspirational ingenuity of Linus Yale Sr. and Linus Yale Jr.” Yale website Securing one's valuables was big business in the nineteenth century. Locksmiths were determined to get one up on the opposition by devising a superior lock to their rivals' devices. In 1847, Linus Yale Sr. (1797-1858) opened the Yale Lock Shop in Newport, New York. He was interested in bank safe locks and began looking into the pin tumbler lock that had been used by the Egyptians over 4,000 years ago. The Egyptians' locks had two major shortcomings—they were wooden and bulky, with some measuring 23.5 inches (60 cm) in length. His early attempts to improve the design focused on incorporating a pin tumbler into the case of the lock, which could then be opened with a round, fluted key. This was only a modest improvement, however, and it was Yale's more...

"... alternating current will undoubtedly drive the hangmen out of business in this state." New York Times, 1888, on a prototype The word electrocution is actually a combination of the words electricity and execution, and was initially only applied to executions performed with electricity, ft was only later that this word was adopted to describe any death caused by electricity. The original idea for the electric chair can be credited to Alfred P. Southwick, a dentist, who observed the death of a man who touched a live electrical terminal while sitting in his dentist's chair. At the same time, a fierce rivalry was developing between Edison and Westinghouse, both of them trying to market their own forms of electricity to the public. Edison (who favored direct current) wanted to show that alternating current was unsafe by having it used for executions. In the late 1880s, he and Harold Pitney Brown, more...

"We shall be able to transport ourselves and families... more securely by air than by water." George Cayley, "On Aerial Navigation 1809-10" Born into a wealthy family in Yorkshire, northern England, George Cayley (1773-1857) was a prolific inventor with an interest in human flight. He devised a heavier-than-air flying machine, with a wing to provide lift, a fuselage in which a pilot could sit, and a cruciform tail for balance and control. In 1804 he built a glider based on this design, with a kite for a wing and a pole some 5 feet (1.5 m) long as the fuselage. This seems to have flown down slopes unmanned, with varying weights of ballast onboard, although Cayley recorded that in later experiments with similar but larger gliders a man running into "a gentle breeze" had found himself lifted off the ground "for several yards." The originality of Cayley's design lay in more...

Man is a social being. He is always eager to see his relatives and friends. In olden days people did not like to take long journeys. There were no quick means of travelling. In the beginning legs were man's means of travelling. He was never satisfied with his legs. Next to legs came animals, horse, camel, elephant, ox, donkey, pony and yak. All have been serving us since ancient times. On the plains we use horse. But in desert the camel is the only means of travelling.  In villages there are no roads. People make use of bullock cart. In the same way people make use of horse. Pony is generally used on mountains. Animals have lost their importance at present as a mode of travelling. We do not use them as means of travelling. We like to travel by train or motor car. Why is it so? The reason more...

The police department is an important department of the Government. The policeman is the guardian of law and order. It is a terror for anti-social elements; It is a friend and a guide to the law- abiding citizens. There are police stations in all the towns. Every station has an in charge of a station office. He is helped in his work by a number of policemen under him. The policeman puts on khaki uniform, khaki cap and strong black shoes. He carries a small thick stick or gun in his hand. He is generally tall and healthy The policemen are in charge of certain areas. They have to keep a watch on the activities of all doubtful characters. If there is any fight and disturbance in his area, he at once runs to the place and stops it. If the people do not obey him, he takes them to more...

Since independence India has taken long steps forward in the field of science and technology. This advance is to be noted in the fields of agriculture, medicine, electronics and many others. But India's achievement has been most spectacular in the field of defence. The main objective or aim of India's defence policy is promoting and sustaining durable peace in the sub-continent and equipping the defence forces adequately to safeguard against foreign aggression. It was April 11, 1999 when India successfully testified to extend the range of AGNI-II, AGNI-1 was successfully launched on may 22, 1989. The then Defence Minister said Agni-11 was perfectly launched at 9.47 a.m. from a new launching site (Ic-4  at Wheeler Island) on the Orissa coast. The two stage missile, carrying a substantial payload, reached the point of impact in 11 minutes as scheduled, he said. It is surface to surface, intermediate range ballistic missile (IRBM). more...

The Julian year (introduced by Julius Caesar in 45 B.C.E.) contained exactly 365.25 days and had a leap year every fourth year (when the year number was divisible by four). But the actual year is 365.24219879 days long and thus the Roman calendar gradually became out of step with reality. By the sixteenth century, the calendar was ten days adrift from the seasons. In 1576 Pope Gregory XIII assembled a commission of astronomers, mathematicians, and clergy, and this advisory body eventually adopted a plan suggested by the Calabrian physician Luigi Lilio, who was also known as Aloysius Lilius. On February 24, 1582, the pope declared that Thursday, October 4, 1582, was to be followed by Friday October 15. From that date, century leap years would only be allowed if the year number was exactly divisible by 400. Thus, 2000 was a leap year, to be followed by 2400,2800, and so more...

In India, there is a parliamentary system of government, according to which the party with the highest majority through a general election is entitled to form the government and its leader becomes the Prime Minister of the country. The  second largest party becomes the opposition party and its leader enjoys the status of the leader of opposition. The ruling party (the government) during Its tenure is free to determine the policies and programmes and make decisions for the welfare of the common people. The opposition parties have a very significant role in a democracy, because they are the representatives of the people to safeguard their interests. Time to time, they criticize the government in case it fails to keep its promises. The opposition parties also warn the government if they think it necessary. Sometimes they show their protest too against the government. Thus they try to keep the government aware more...

One of the remarkable inventions of modern science is certainly radio. Radio is a kind of wireless telegraphy on which, instead of sound, we hear words. With the help of a radio instrument we can hear news, music, speeches etc. from a distance. The credit for inventing this wonderful work goes to the Italian scientist, Marconi. He invented it in 1901. Radio is a useful medium of entertainment. We can listen to songs, music, plays, news, weather reports etc. on it. Radio programmes are relayed from radio stations. Radio has an educative value. We can learn a lot from the views of eminent persons. Also educational speeches are relayed from time to time which are very useful for the audience. The weather forecasts are also very important for sailors, pilots and fishermen. They can be cautioned against any incoming bad weather. Even a ship in distress can send out messages more...

A mosquito is a small insect. It is found mainly in hot and moist parts of the world. Mosquitoes disturb our  sleep at night. Mosquitoes like to live in dark, damp and dirty places. Mosquitoes are a great nuisance to us. Female mosquitoes breed in dirty drains, stagnant water, dark and damp bushes. We are always afraid of mosquito bites. Their buzzing sound is quite disturbing to the ears and their bites are painful to the skin. Only female mosquitoes can suck blood by entering their sharp stings into the skin of their prey. The male mosquitoes cannot do so as they have blunt stings. Mosquitoes are very harmful to men. They spread different diseases like malaria and yellow fever. Very recently, they have been reported to spread dangerous diseases called encephalitis and dengue. To get rid of mosquitoes and their painful bites, we should sleep under mosquito nets and more...