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acid action alkalies animal appears ascer ascertained atmosphere attraction axis ball body bulb called cause centre of gravity centrifugal force chemical circle colour combination common conductor considerable contained copper degree direction distance diurnal motion earth eclipse effect elastic electric currents electric fluid electrified equal equator experiments fall feet fixed force friction fulcrum galvanic glass globe greater hand heat inches instance instrument iron kind length lever machine magnetic means mechanical power mercury meridian metals moon motion move nature needle nitric acid north pole observed orbit particles passing phial philosophers piece planets plates polar circles potass pressure produced properties proportion pulley quantity render resistance revolve round rise round the sun shock silver situated south pole specific gravity stars substances sun's rays supposed surface suspended temperature thermometer tion tricity tube vapour velocity vessel Voltaic pile weather weight wheel wind wire zinc
Page 116 - ... circle in the same space of time that the axle describes a small one, therefore the power is increased in the same proportion as the circumference of the wheel is greater than that of the axle. If the velocity of the wheel...
Page 189 - ... been exposed, is taken away, it throws out a pencil of flame so long, that with this burning machine in my hand, I have taken above sixty steps in walking about my room. When it is electrified strongly, I can take it into another room, and there fire spirits of wine with it.
Page 189 - ... is taken away, it throws out a pencil of flame so long, that with this burning machine in my hand, I have taken above sixty steps in walking about my room. When it is electrified strongly, I can take it into another room, and there fire spirits of wine with it. If, while it is electrifying, I put my finger, or a piece of gold which I hold in my hand, to the nail, I receive a shock which stuns my arms and shoulders.
Page 74 - Aries the Ram, Taurus the Bull, Gemini the Twins, Cancer the Crab, Leo the Lion, Virgo the Virgin, Libra the Balance, Scorpio the Scorpion, Sagittarius the Archer, Capricornus the Goat, Aquarius the Waterbearer, and Pisces the Fishes...
Page 123 - ... to the right or to the left, according as its eye is on the right or the left hand. This is the usual process, and in it every needle passes individually under the finger of the operator. A small alteration expedites the process considerably ; the child puts on the forefinger of its right hand a small cloth cap or finger-stall, and, rolling from the heap from six to twelve needles...
Page 105 - ... called in geometry a parabola. But when the ball is thrown perpendicularly upwards, it will descend perpendicularly; because the force of projection, and that of gravity, are in the same line of direction. We have noticed the centres of magnitude and of motion; but I have not yet explained to you what is meant by the centre of gravity.
Page 163 - In the year 1774, the following question was proposed by the Electoral Academy of Bavaria as the subject of a prize dissertation : — ' Is there a real and physical analogy between electric and magnetic forces ; and, if such analogy exist, in what manner do these forces act upon the animal body...
Page 119 - Yes ; friction is the resistance which bodies meet with in rubbing against each other ; there is no such thing as perfect smoothness or evenness in nature: polished metals, though they wear that appearance, more than any other bodies, are far from really possessing it; and their inequalities may frequently be perceived through a good magnifying glass. When, therefore, the surfaces of the two bodies come into contact, the prominent parts of the.
Page 72 - ... of our years. His diameter is 79,000 miles. This planet is surrounded by a luminous ring, the nature of which astronomers are much at a loss to conjecture : he has seven moons. Lastly, we observe the Georgium Sidus, discovered by Sir William Herschel, and which is attended by six moons.
Page 174 - From the preceding facts we may likewise collect that this conflict performs circles ; for without this condition, it seems impossible that the one part of the uniting wire, when placed below the magnetic pole, should drive it towards the east, and when placed above it towards the west; for it is the nature of a circle that the motions in opposite parts should have an opposite direction.