Invention

h a point, and a linen thread "an ell or more long," hanging from the stick. The lower end of the thread being made to hang "a thumb breadth dista

from the body; so that by moving the ball back and forth, the lower

hat Guericke's feat is a little hard to class. It is classed by many as an invention, however, and the present author is inclined to class it so; because there seems no reason to doubt that Guericke first conceived the idea of doing what he did do, and that he did produ

have covered a wider field, and to have been more distinctly an inventor. His celebrated experiment of holding two hollow hemispheres together, then exhausting the air from the hollow sphere thus formed, and the

on. Of Guericke's discoveries and inventions, the only one that has survived as a concrete apparatus is the air pump; but it is doubtful if the direct influence

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ining water, under which a fire is burning, support a ball placed immediately above the tube, and make it seem to dance. In another apparatus, a hollow sphere into which steam has arisen from what we now call a boiler, is supported on a horizontal or vertical axis, and provided with tubes that protrude from the sphere, and are bent at right angles to the radius and also to the pivot. The inner ends of these tubes lie within the sphere, so that the steam passes from the sphere through the tubes. As soon as this happens, the sphere takes up a rapid rotation

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med de Caus published a book in which he showed a hollow sphere into which water could be introduced through an orifice that could then be closed; the sphere carrying a vertical tube that dipped into the water at its lower end, and ending in a small nozzle at its upper end. When a fire was started under the sph

the revolution of Hero's hollow sphere was communicated to a series of pestles in mortars, and put to the useful w

freeing the mines from water were extremely great, and the desirability of overcoming them was equally so. In Savery's engine, there were two boilers in which steam was raised, and two receivers communicating with them. Steam being admitted to one receiver, the connection with the boiler was shut off by a valve, and a cold jet was then suddenly thrown on the receiver, condensing the steam and forming a partial vacuum. Th

harge stream was made to fall on a mill-wheel, as though from a natural waterfall. Several of

considerable advance on previous engines. It comprised a separate boiler and furnace, a separate cylinder and piston, means for condensing the steam in the cylinder by injecting water into it, and a system of self-acting valves that were opened and closed by a long beam that was moved by the piston. Furthermore, this beam communicated motion to a pum

op to the atmosphere as in the others, but he used higher pressures of steam, and arranged a four-way cock between the bottoms of the two cylinders in such a way that the bottom of each cylinder, in its turn, was co

ld's

stroke was wholly avoided. He covered the cylinder entirely, and surrounded it with an external cylinder kept always full of steam, that maintained the cylinder at a high temperature. The steam, instead of bei

f at any desired part of the stroke, and the steam allowed to complete the rest of the stroke by virtue of its expansive force. T

apparatus whereby the reciprocating motion of the piston could be converted into a rotary motion. Watt was able to accomplish both feats, and to connect the bottom and top of the cylinder a

d until after all those men had died whose names have just been mentioned. It is inconceivable that any of those men could really have expected that their work was to have even a small fraction of the influence on mankind that it actually has had. The influence of Watt's work became visible to some degree before he died, and became clearly visible not very long after he had died; so clearly vi

them. It was by the knowledge which they gleaned regarding the properties of steam and air and water and iron, regarding the laws of motion and heat and work and force and weight and mass, that the inventors' experiments were guided. It is true that the science of physics was then in its infancy, as we realize with the knowledge of the science today; but Aristotle in the days of Greece, and Archimedes and Hero later, and Galileo and

are classified, they are not useful until some use is found for them. The data in card-indexes are mere unrelated facts, and are almost useless, until they have been classified and arranged in boxes alphabetically labeled. Then they are useful whenever any use is found; when, for instance, some one is seeking information on a certain subject. In this condition, data are like material substances, in

tions, experiments and researches have ended in nothing definite:-most of them, in all probability, have not even established facts. The investigations that we studied about when boys were such as those of Archimedes, that presented us with inventions, in the form of useful and usable laws. No appreciable difference is apparent between the mental operations of Archimedes in inventing these laws and his mental operations in inventing his screw: for in both cases the mental o

ould be hammered so as to have a point and a sharp edge. He had to know also something about the flesh of a man: he had to know that if his flesh was struck with a sharp hard instrument, it would be bruised, and the man injured, and maybe killed. Similarly, the inventor of the gun, and the inventor of printing, and the inventors of steam engines, had to know a good deal about

hine of civilization is so vast and so complex, that the amount of knowledge which anyone of us needs in mere daily

were as good as those of today; such things, for instance as temples and pyramids and stationary objects in general. But the ancients did not understand motion clearly, especially irregular motion; and they

n producing motion. Dynamics is a branch of the science of mechanics, and a most difficult branch. It is built on the observations, calculations

illumination and the development of inventions for producing it; the science of acoustics made possible the solution of our problems of sound, including music, and the invention of acoustic and musical instruments; the science of heat made possible the invention of all the complex and powerful steam and gas engines that have revolutionized so

and water into steam: the mathematical laws which showed how much water was needed to secure a certain amount of steam, for instance, and how a certain desired pressure of steam could be secured, had first to be comprehended and then to be followed. In order to have boilers and engines so designed as to pr

agency could be kept separate from the phenomena caused by another agency, the laws underlying both had to be understood. The science of light could not be developed until the action of heat was fairly well understood; dynamics had to wait on statics; Newton could not have contributed what he did to astronomy, unless the science

le to start on still further expeditions of discovery into the unknown. As the common basis of all quantitative work is mathematics, the common basis of all the physical sciences is mathematics. This makes all the physical sciences interdependent, despite the fact that each is independent of the others. Each one of the physical sciences has contributed its part to building the machine of civilization; the part that each has specially contributed can be clearly specified; and yet, since the mac

ry to have taken up Bacon's work and carried it further on. Following Newton, only a few great investigators can be seen in the seventeenth century; but in the eighteenth, b

at the vibrations of a pendulum were nearly isochronous, and could be used to measure the lapse of time; and that Galileo's son (as well as Dr. Hooke, Huygens and a London mechanic named Harris, in the early part of the seventeenth century) made cl

ing to heat and light; but, by reason of the interdependence of all the physical sciences, their investigations led them automatically into the allied fields of acoustics and elec

hine." It is an interesting illustration of the addition of invention to investigation, in that its end was-merely investigation; and it reminds us of a fact that

of an upright with a pulley at its upper end over which passed a cord, to both ends of which weights could be attached. In any given experiment, a weight was attached to one end and allowed to fall free; but another weight could automatically be attached to the other end by a simple device, when the first weight had fallen through any predetermined distance. If the added weight were equal to the first weig

ainly because of the opposition from the type-founders; so that Ged died without realizing that he had accomplished anything. Ged's invention was not put to practical use for nearly fifty years after his death; but after that, its employment extended rapidly over the civilized world. Ged's experience was bitte

to this theory, the pressure of any gas is due to the impact of its molecules against the walls of the vessel containing it. Naturally, the greater the density of the gas, and the greater the velocity of the molecules, th

develop it into a system of administration, in spite of opposition of all kinds, especially inertia. He ruled till 1688. He found Brandenburg unimportant, disordered and poor; he left Brandenburg comparatively rich, with a good army, an excellent corps of administrators, a very efficient gov

tage of his father's work and be crowned as King of Prussia. He was followed by his son, King Frederick William I

ng the soldiers that a regiment or division could be handled like a coherent and even rigid thing, directed accurately and quickly at a pre-determined point, and made to hit an enemy at that point with a force somewhat like the blow of an enormous c

d, as great as that of almost any other contemporary inventions that can be specified. Their immediate influence was to make it possible for the son

eless, the doings of Prussia and the German Empire have had an enormous influence up to the present time; and that, though the empire itself has ceased, the influence of its polici

dly help being good, in view of the training he had received and the military atmosphere in which he had been born and bred. But no amount of training could have given Frederick the brilliant and yet correct imagination that enabled him to see entire situations clearly and accurately with his mental eye; that enabled him to form a correct picture of the mission in

ick's conception came straight from the devil, it was a brilliant conception, nevertheless, as the conceptions of the devil himself are popularly supposed to be. So original in c

. But it is the verdict of history that even these advantages were far from sufficient to explain his victories; that his victories cannot be explained except on the ground that Frederick showed a generalship superior to that of his foes. In what did its superiority consist? A careful study of his campaigns, even if it be not in detail, shows that Frederick was able to invent better plans than his adversaries, to invent them more quickly, and to carry them int

in results occurred about 1746, in the town of Leyden, where Muschenbroek invented a device that made possible the accumulating and preserving of charges of electricity. This applia

with it. Among these were the firing of gunpowder by the electric spark that passed when both surfaces of tin foil were connected by an external conductor; a

and that the spark was caused by the transfer of electricity from one coating to the other. These discoveries were as much as any one discoverer might reasonably be expected to contribute; but Franklin soon followed them by his discovery of the power of points to

in Philadelphia. The erection of the spire being delayed, his imagination presented to his mind the picture of a kite flying near the cloud, and the charge flowing down the cord, made into a conductor by the accompanying rain. Forthwith, he embodied his conception in definite form by preparing a kite to which was connected a long cord, that ended with a piece of non-conducting silk, that was to be held in the hand, and kept dry if possible, and a key that was secured to the

ent may here be pointed out. To the eye of a casual obse

on in what we now call "lightning rods," by erecting on the highest points of houses thin metal rods or conductors, the lower ends of which were buried in the earth, while their upper ends were sharpened to points, and made to project upward, abo

of the earliest important discoveries that followed (made by Mr. Cavendish) was that the electrical spark could decompose water and atmospheric air, and make water by explo

ue. In investigating the cause of this phenomenon, Volta discovered that if the lower ends of two dissimilar metals were immersed in a liquid they would assume opposite electrical states; so that if their outer ends were joined by a conducting wire, electri

rk was mainly in making investigations of the phenomena of heat. In the course of them he discovered the important fact that different substances require different amounts of heat to be applied to a given mass to raise its temperature 1°. From this disc

was that of the oxygen that became associated with the metal in the form of rust. He therefore disproved the theory formerly loosely held that the increase in weight was due to the escape of a spirituous substance which the chemists of that day imagined to depart from the metal, and cal

tined on a false accusation. He requested a brief respite, in order to complete an important experiment, and was told in answer t

n the eighteenth century A. D., as in Egypt and Assyria long before the eighteenth century B. C. About 1738 Dr. Lewis Paul invented and patented a simple mechanism that anyone with imagination could have invented at any time during the two or three thousand years before, in which the filaments were drawn between rollers. The invention seems to have been moderately successful from the start; for it is stated that in 1742 a spinning mill was in operation in Birmingham in which ten girls were employed, and in which the motive power was supplied by two asses. Paul's invention

, the enemy making no decided move to drive him off. Finally, on March 4, 1776, having conceived a plan that promised success to him, he suddenly seized and fortified Dorchester Heights, about two miles south of Boston, from which he could command the whole of Boston and

g at a map of Boston in the quiet and safety of a library, but there must have been a great deal of merit and originality in it; for it took a British major-general completely by surprise, an

d with his occupying Trenton, and Howe occupying New York with the bulk of his forces. Washington had only a little more than 4,000 men, while Howe had 30,000. Washington's troops were discouraged, half-ragged, underfed and untrained; Howe's were elated, well clad, well fed and thoroughly trained. Washington was in as dangerous a plight as can easily be imagined. He extricated himself by conceiving and carryi

gust 14 he received a letter written in July by Admiral Comte de Grasse, then in the West Indies, saying that he would start with his fleet and a force of troops for Chesapeake Bay on August 13. Washington knew that the British General Cornwallis was entrenched at Yorktown, near the mouth of the Chesapeake, with a force considerably inferior to his own. He instantly proceeded to embody in action an idea that

2, inflated soap-bubbles with hydrogen gas, but went no further. The subject of making balloons filled with hydrogen was widely discussed; but the first balloon really to rise was the hot-air balloon invented by Joseph and Stephen Montgolfier. This balloon made a successful ascent on June 5, 1783, carrying the two brothers, flew about ten minutes, and alighted safe, after a trip of

d, originating in the conception by the Rev. Dr. Cartwright of the possibility of doing much more weaving by mechanical power than by hand, then constructing the machine to accomplis

bottom of the cylinder, which was connected by a small pipe with a small pump, by which more liquid could be forced in. When the pump was operated the pressure per square inch on the piston of the pump was communicated to each square inch of the large piston in the press, and a force exe

eighteenth century, especially in England. In these experiments, the invention by Archimedes of the hydrostatic principle of buoyancy supplied the starting-point, and gave an excellent illustration of the influence of invention on history: for from experiments and in

achine and the cotton gin; the former invented by Andrew Meikle in 1788, and the latter by Eli Whitney in 1793. It would be hard to decide with knowledge as to which has had the greater influe

lready in existence. This was the invention of lithography, or printing from stone, made by Alois Senefelder in 1796. The first thing printed by him was a piece of music. While this

youthful and prestigeless captain opposed this plan with a vehemence and convincingness that came to be familiarly known a few years later, and proposed in place of it a plan that he had himself conceived and embodied in a concrete form. His plan consisted in the main merely in mounting some guns on a point of land that he designated, from which they could command the British war-ships in the harbor;

etween Napoleon's plan and that of th